ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF FirstRanker.com - FirstRanker's Choice
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DEPARTMENT OF MECHANICAL ENGINEERING
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding. FirstRanker.com - FirstRanker's Choice
?
DEPARTMENT OF MECHANICAL ENGINEERING
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
8 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
8 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
9 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
8 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
9 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
10 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
8 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
9 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
10 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
11 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
8 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
9 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
10 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
11 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
12 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power FirstRanker.com - FirstRanker's Choice
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DEPARTMENT OF MECHANICAL ENGINEERING
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
8 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
9 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
10 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
11 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
12 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power
13 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Terms and Nomenclature
1. Crest: It is the peak edge of a screw thread that connects the adjacent flanks at the top. 2. Root: It is the bottom edge of the thread that connects the adjacent flanks at the bottom. 3. Flank or side: It is the straight portion of the surface, on either side of the screw thread. 4. Angle of the thread: It is the angle included between the sides of two adjacent threads measured on an axial plane. 5. Depth of the thread: It is the distance between the crest and the root measured at Right angle to the axis. It is equal to half the difference between the outer diameter and the core diameter. 6. Major diameter or outside diameter: It is the diameter of the imaginary coaxial cylinder, which would bind the crests of an external or internal thread. 7. Minor or core or root diameter: It is the diameter of the imaginary coaxial cylinder; this would bind the roots of an external thread or of an internal thread. 8. Pitch diameter: It is the diameter of the imaginary coaxial cylinder that can be passed so as to cut the thread, that the width of the cut thread will be equal to the Width of the groove. 9. Pitch: It is the axial distance between a point on one thread and the corresponding Point on the next thread. It may be indicated as the distance from crest or from root of two adjacent threads. 10. Lead: It is the distance measured parallel to the axis from a point on a thread to the corresponding point on the same thread for one complete revolution. In other words, it is axial distance a screw advances in one revolution. 11. External thread: It is the thread on the outside surface of a member such as bolt, studs or screw. 12. Internal thread: It is the thread on the inside surface of a member such as nut or threaded hole. 13. Right hand thread: Right hand thread if turned clockwise direction advances into a threaded hole. It abbreviated as RH. 14. Left hand thread: Left hand thread if turned anticlockwise direction advances into a threaded hole. It abbreviated as LH. FirstRanker.com - FirstRanker's Choice
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DEPARTMENT OF MECHANICAL ENGINEERING
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
8 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
9 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
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11 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
12 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power
13 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Terms and Nomenclature
1. Crest: It is the peak edge of a screw thread that connects the adjacent flanks at the top. 2. Root: It is the bottom edge of the thread that connects the adjacent flanks at the bottom. 3. Flank or side: It is the straight portion of the surface, on either side of the screw thread. 4. Angle of the thread: It is the angle included between the sides of two adjacent threads measured on an axial plane. 5. Depth of the thread: It is the distance between the crest and the root measured at Right angle to the axis. It is equal to half the difference between the outer diameter and the core diameter. 6. Major diameter or outside diameter: It is the diameter of the imaginary coaxial cylinder, which would bind the crests of an external or internal thread. 7. Minor or core or root diameter: It is the diameter of the imaginary coaxial cylinder; this would bind the roots of an external thread or of an internal thread. 8. Pitch diameter: It is the diameter of the imaginary coaxial cylinder that can be passed so as to cut the thread, that the width of the cut thread will be equal to the Width of the groove. 9. Pitch: It is the axial distance between a point on one thread and the corresponding Point on the next thread. It may be indicated as the distance from crest or from root of two adjacent threads. 10. Lead: It is the distance measured parallel to the axis from a point on a thread to the corresponding point on the same thread for one complete revolution. In other words, it is axial distance a screw advances in one revolution. 11. External thread: It is the thread on the outside surface of a member such as bolt, studs or screw. 12. Internal thread: It is the thread on the inside surface of a member such as nut or threaded hole. 13. Right hand thread: Right hand thread if turned clockwise direction advances into a threaded hole. It abbreviated as RH. 14. Left hand thread: Left hand thread if turned anticlockwise direction advances into a threaded hole. It abbreviated as LH.
14 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
V- THREADS British standard whit worth thread (BSW) This thread was introduced by Sir Joseph whit worth, and was standardized as British standard thread. It has a thread angle of 55 degree and is rounded equally at crest and roots. British Association threads (B.A Threads) The angle between flanks is 47.5 degree. These threads are to supplement BSW and have fine pitches. They are used on screws for precision work. American standard threads (or) sellers thread The thread angle is 60 degree and both the crests and roots are kept flat. The sellers thread has been in use in USA and Canada. Unified screw threads The countries UK, U.S.A and Canada came to an arrangement for a common screw thread system with the included angle of 60 degree and designated as unified screw thread in the year 1949. The thread on the bolt is rounded off at the crest and root and the thread in the nut is rounded off at the root but the crest is left flat. This thread is very important in the motor and aeroplane industries and in chemical engineering. Unified thread can be either coarse (UNC) or fine (UNF) and unified national extra fine (UEF). ISO Metric Thread This is Indian standard thread for ISO (International Standard Organization). The included angle is 60 0 and the crests are flat and roots are round. Metric threads are grouped into diameter pitch combination differentiated by the pitch applied to specific diameters. There are coarse, constant, fine pitch series available. ISO metric threads are defined by nominal size (Basic major diameter) and pitch both expressed in millimeters. for example, a 10mm diameter, 1.25 pitches is expressed as M10?1.25. SQUARE THREADS Basic square thread The sides of these threads are normal to the axis and parallel to each other. The depth and the thickness of the thread are equal to half pitch. A square thread is designated by the letter SQ followed by nominal diameter pitch. For example a square thread of nominal diameter 30mm and pitch 6mm is designated as SQ 30?6. Acme Thread It is a modified form of square thread. It is easier to cut and is much stronger than square thread. It has a 29 0
thread angle. This inclined sides of the thread facilitate quick and early engagement and disengagement. It is used for power screws like lead screw of lathe, jackscrews, bench vices and valve operating screws. FirstRanker.com - FirstRanker's Choice
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DEPARTMENT OF MECHANICAL ENGINEERING
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
8 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
9 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
10 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
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1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
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Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power
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Terms and Nomenclature
1. Crest: It is the peak edge of a screw thread that connects the adjacent flanks at the top. 2. Root: It is the bottom edge of the thread that connects the adjacent flanks at the bottom. 3. Flank or side: It is the straight portion of the surface, on either side of the screw thread. 4. Angle of the thread: It is the angle included between the sides of two adjacent threads measured on an axial plane. 5. Depth of the thread: It is the distance between the crest and the root measured at Right angle to the axis. It is equal to half the difference between the outer diameter and the core diameter. 6. Major diameter or outside diameter: It is the diameter of the imaginary coaxial cylinder, which would bind the crests of an external or internal thread. 7. Minor or core or root diameter: It is the diameter of the imaginary coaxial cylinder; this would bind the roots of an external thread or of an internal thread. 8. Pitch diameter: It is the diameter of the imaginary coaxial cylinder that can be passed so as to cut the thread, that the width of the cut thread will be equal to the Width of the groove. 9. Pitch: It is the axial distance between a point on one thread and the corresponding Point on the next thread. It may be indicated as the distance from crest or from root of two adjacent threads. 10. Lead: It is the distance measured parallel to the axis from a point on a thread to the corresponding point on the same thread for one complete revolution. In other words, it is axial distance a screw advances in one revolution. 11. External thread: It is the thread on the outside surface of a member such as bolt, studs or screw. 12. Internal thread: It is the thread on the inside surface of a member such as nut or threaded hole. 13. Right hand thread: Right hand thread if turned clockwise direction advances into a threaded hole. It abbreviated as RH. 14. Left hand thread: Left hand thread if turned anticlockwise direction advances into a threaded hole. It abbreviated as LH.
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V- THREADS British standard whit worth thread (BSW) This thread was introduced by Sir Joseph whit worth, and was standardized as British standard thread. It has a thread angle of 55 degree and is rounded equally at crest and roots. British Association threads (B.A Threads) The angle between flanks is 47.5 degree. These threads are to supplement BSW and have fine pitches. They are used on screws for precision work. American standard threads (or) sellers thread The thread angle is 60 degree and both the crests and roots are kept flat. The sellers thread has been in use in USA and Canada. Unified screw threads The countries UK, U.S.A and Canada came to an arrangement for a common screw thread system with the included angle of 60 degree and designated as unified screw thread in the year 1949. The thread on the bolt is rounded off at the crest and root and the thread in the nut is rounded off at the root but the crest is left flat. This thread is very important in the motor and aeroplane industries and in chemical engineering. Unified thread can be either coarse (UNC) or fine (UNF) and unified national extra fine (UEF). ISO Metric Thread This is Indian standard thread for ISO (International Standard Organization). The included angle is 60 0 and the crests are flat and roots are round. Metric threads are grouped into diameter pitch combination differentiated by the pitch applied to specific diameters. There are coarse, constant, fine pitch series available. ISO metric threads are defined by nominal size (Basic major diameter) and pitch both expressed in millimeters. for example, a 10mm diameter, 1.25 pitches is expressed as M10?1.25. SQUARE THREADS Basic square thread The sides of these threads are normal to the axis and parallel to each other. The depth and the thickness of the thread are equal to half pitch. A square thread is designated by the letter SQ followed by nominal diameter pitch. For example a square thread of nominal diameter 30mm and pitch 6mm is designated as SQ 30?6. Acme Thread It is a modified form of square thread. It is easier to cut and is much stronger than square thread. It has a 29 0
thread angle. This inclined sides of the thread facilitate quick and early engagement and disengagement. It is used for power screws like lead screw of lathe, jackscrews, bench vices and valve operating screws.
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Buttress Thread The profile of this thread is a combination of square and V- threads. It combines the low frictional of square and ability to transmit power of square thread and the strength of V ? thread. It is used to transmit load in uni-direction. These threads are used in screw press, vices.
Knuckle Thread It is also a modification of square thread. The sharp corners of square thread are rounded off. This thread is used where heavy wear rough use is expected. The thread can be rolled or cast easily. It is used in railway carriage coupling screws, light bulbs and sockets, bottle caps etc and also objects made of brittle materials as glass, plastic, porcelains etc.
Types of thread profiles
Keys Keys are machine elements used to prevent relative rotational movement between a shaft and the parts mounted on it, such as pulleys, gears, wheels, couplings, etc. for making the joint, keyways are cut on the surface of the shaft and in the hub of the part to be mounted. After positioning the part on the shaft such that, both the keyways are properly aligned, the key is driven from the end, resulting in a firm joint. For mounting a part at any intermediate location on the shaft, first the key is firmly placed in the keyways of the shaft and then the part to be mounted is slid from one end of the shaft, till it is fully engaged with the key. Keys are classified into three types. 1. Saddle keys I. flat saddle key II. hollow saddle key FirstRanker.com - FirstRanker's Choice
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DEPARTMENT OF MECHANICAL ENGINEERING
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
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PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
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To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
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ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
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Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
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Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
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The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
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The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
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1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
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Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power
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Terms and Nomenclature
1. Crest: It is the peak edge of a screw thread that connects the adjacent flanks at the top. 2. Root: It is the bottom edge of the thread that connects the adjacent flanks at the bottom. 3. Flank or side: It is the straight portion of the surface, on either side of the screw thread. 4. Angle of the thread: It is the angle included between the sides of two adjacent threads measured on an axial plane. 5. Depth of the thread: It is the distance between the crest and the root measured at Right angle to the axis. It is equal to half the difference between the outer diameter and the core diameter. 6. Major diameter or outside diameter: It is the diameter of the imaginary coaxial cylinder, which would bind the crests of an external or internal thread. 7. Minor or core or root diameter: It is the diameter of the imaginary coaxial cylinder; this would bind the roots of an external thread or of an internal thread. 8. Pitch diameter: It is the diameter of the imaginary coaxial cylinder that can be passed so as to cut the thread, that the width of the cut thread will be equal to the Width of the groove. 9. Pitch: It is the axial distance between a point on one thread and the corresponding Point on the next thread. It may be indicated as the distance from crest or from root of two adjacent threads. 10. Lead: It is the distance measured parallel to the axis from a point on a thread to the corresponding point on the same thread for one complete revolution. In other words, it is axial distance a screw advances in one revolution. 11. External thread: It is the thread on the outside surface of a member such as bolt, studs or screw. 12. Internal thread: It is the thread on the inside surface of a member such as nut or threaded hole. 13. Right hand thread: Right hand thread if turned clockwise direction advances into a threaded hole. It abbreviated as RH. 14. Left hand thread: Left hand thread if turned anticlockwise direction advances into a threaded hole. It abbreviated as LH.
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V- THREADS British standard whit worth thread (BSW) This thread was introduced by Sir Joseph whit worth, and was standardized as British standard thread. It has a thread angle of 55 degree and is rounded equally at crest and roots. British Association threads (B.A Threads) The angle between flanks is 47.5 degree. These threads are to supplement BSW and have fine pitches. They are used on screws for precision work. American standard threads (or) sellers thread The thread angle is 60 degree and both the crests and roots are kept flat. The sellers thread has been in use in USA and Canada. Unified screw threads The countries UK, U.S.A and Canada came to an arrangement for a common screw thread system with the included angle of 60 degree and designated as unified screw thread in the year 1949. The thread on the bolt is rounded off at the crest and root and the thread in the nut is rounded off at the root but the crest is left flat. This thread is very important in the motor and aeroplane industries and in chemical engineering. Unified thread can be either coarse (UNC) or fine (UNF) and unified national extra fine (UEF). ISO Metric Thread This is Indian standard thread for ISO (International Standard Organization). The included angle is 60 0 and the crests are flat and roots are round. Metric threads are grouped into diameter pitch combination differentiated by the pitch applied to specific diameters. There are coarse, constant, fine pitch series available. ISO metric threads are defined by nominal size (Basic major diameter) and pitch both expressed in millimeters. for example, a 10mm diameter, 1.25 pitches is expressed as M10?1.25. SQUARE THREADS Basic square thread The sides of these threads are normal to the axis and parallel to each other. The depth and the thickness of the thread are equal to half pitch. A square thread is designated by the letter SQ followed by nominal diameter pitch. For example a square thread of nominal diameter 30mm and pitch 6mm is designated as SQ 30?6. Acme Thread It is a modified form of square thread. It is easier to cut and is much stronger than square thread. It has a 29 0
thread angle. This inclined sides of the thread facilitate quick and early engagement and disengagement. It is used for power screws like lead screw of lathe, jackscrews, bench vices and valve operating screws.
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Buttress Thread The profile of this thread is a combination of square and V- threads. It combines the low frictional of square and ability to transmit power of square thread and the strength of V ? thread. It is used to transmit load in uni-direction. These threads are used in screw press, vices.
Knuckle Thread It is also a modification of square thread. The sharp corners of square thread are rounded off. This thread is used where heavy wear rough use is expected. The thread can be rolled or cast easily. It is used in railway carriage coupling screws, light bulbs and sockets, bottle caps etc and also objects made of brittle materials as glass, plastic, porcelains etc.
Types of thread profiles
Keys Keys are machine elements used to prevent relative rotational movement between a shaft and the parts mounted on it, such as pulleys, gears, wheels, couplings, etc. for making the joint, keyways are cut on the surface of the shaft and in the hub of the part to be mounted. After positioning the part on the shaft such that, both the keyways are properly aligned, the key is driven from the end, resulting in a firm joint. For mounting a part at any intermediate location on the shaft, first the key is firmly placed in the keyways of the shaft and then the part to be mounted is slid from one end of the shaft, till it is fully engaged with the key. Keys are classified into three types. 1. Saddle keys I. flat saddle key II. hollow saddle key
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2. Sunk keys I. taper sunk keys II. parallel sunk keys III. woodruff keys 3. Round keys
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
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ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
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Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
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Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
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The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
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The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
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1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
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Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power
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Terms and Nomenclature
1. Crest: It is the peak edge of a screw thread that connects the adjacent flanks at the top. 2. Root: It is the bottom edge of the thread that connects the adjacent flanks at the bottom. 3. Flank or side: It is the straight portion of the surface, on either side of the screw thread. 4. Angle of the thread: It is the angle included between the sides of two adjacent threads measured on an axial plane. 5. Depth of the thread: It is the distance between the crest and the root measured at Right angle to the axis. It is equal to half the difference between the outer diameter and the core diameter. 6. Major diameter or outside diameter: It is the diameter of the imaginary coaxial cylinder, which would bind the crests of an external or internal thread. 7. Minor or core or root diameter: It is the diameter of the imaginary coaxial cylinder; this would bind the roots of an external thread or of an internal thread. 8. Pitch diameter: It is the diameter of the imaginary coaxial cylinder that can be passed so as to cut the thread, that the width of the cut thread will be equal to the Width of the groove. 9. Pitch: It is the axial distance between a point on one thread and the corresponding Point on the next thread. It may be indicated as the distance from crest or from root of two adjacent threads. 10. Lead: It is the distance measured parallel to the axis from a point on a thread to the corresponding point on the same thread for one complete revolution. In other words, it is axial distance a screw advances in one revolution. 11. External thread: It is the thread on the outside surface of a member such as bolt, studs or screw. 12. Internal thread: It is the thread on the inside surface of a member such as nut or threaded hole. 13. Right hand thread: Right hand thread if turned clockwise direction advances into a threaded hole. It abbreviated as RH. 14. Left hand thread: Left hand thread if turned anticlockwise direction advances into a threaded hole. It abbreviated as LH.
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V- THREADS British standard whit worth thread (BSW) This thread was introduced by Sir Joseph whit worth, and was standardized as British standard thread. It has a thread angle of 55 degree and is rounded equally at crest and roots. British Association threads (B.A Threads) The angle between flanks is 47.5 degree. These threads are to supplement BSW and have fine pitches. They are used on screws for precision work. American standard threads (or) sellers thread The thread angle is 60 degree and both the crests and roots are kept flat. The sellers thread has been in use in USA and Canada. Unified screw threads The countries UK, U.S.A and Canada came to an arrangement for a common screw thread system with the included angle of 60 degree and designated as unified screw thread in the year 1949. The thread on the bolt is rounded off at the crest and root and the thread in the nut is rounded off at the root but the crest is left flat. This thread is very important in the motor and aeroplane industries and in chemical engineering. Unified thread can be either coarse (UNC) or fine (UNF) and unified national extra fine (UEF). ISO Metric Thread This is Indian standard thread for ISO (International Standard Organization). The included angle is 60 0 and the crests are flat and roots are round. Metric threads are grouped into diameter pitch combination differentiated by the pitch applied to specific diameters. There are coarse, constant, fine pitch series available. ISO metric threads are defined by nominal size (Basic major diameter) and pitch both expressed in millimeters. for example, a 10mm diameter, 1.25 pitches is expressed as M10?1.25. SQUARE THREADS Basic square thread The sides of these threads are normal to the axis and parallel to each other. The depth and the thickness of the thread are equal to half pitch. A square thread is designated by the letter SQ followed by nominal diameter pitch. For example a square thread of nominal diameter 30mm and pitch 6mm is designated as SQ 30?6. Acme Thread It is a modified form of square thread. It is easier to cut and is much stronger than square thread. It has a 29 0
thread angle. This inclined sides of the thread facilitate quick and early engagement and disengagement. It is used for power screws like lead screw of lathe, jackscrews, bench vices and valve operating screws.
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Buttress Thread The profile of this thread is a combination of square and V- threads. It combines the low frictional of square and ability to transmit power of square thread and the strength of V ? thread. It is used to transmit load in uni-direction. These threads are used in screw press, vices.
Knuckle Thread It is also a modification of square thread. The sharp corners of square thread are rounded off. This thread is used where heavy wear rough use is expected. The thread can be rolled or cast easily. It is used in railway carriage coupling screws, light bulbs and sockets, bottle caps etc and also objects made of brittle materials as glass, plastic, porcelains etc.
Types of thread profiles
Keys Keys are machine elements used to prevent relative rotational movement between a shaft and the parts mounted on it, such as pulleys, gears, wheels, couplings, etc. for making the joint, keyways are cut on the surface of the shaft and in the hub of the part to be mounted. After positioning the part on the shaft such that, both the keyways are properly aligned, the key is driven from the end, resulting in a firm joint. For mounting a part at any intermediate location on the shaft, first the key is firmly placed in the keyways of the shaft and then the part to be mounted is slid from one end of the shaft, till it is fully engaged with the key. Keys are classified into three types. 1. Saddle keys I. flat saddle key II. hollow saddle key
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2. Sunk keys I. taper sunk keys II. parallel sunk keys III. woodruff keys 3. Round keys
Types of keys
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Bolt and nuts A bolt and nut in combination is a fastening device used to hold two parts together. The body of the bolt, called shank is cylindrical in form, the head; square or hexagonal in shape, is formed by forging. Screw threads are cut on the other end of the shank. Nuts in general are square or hexagonal in shape. The nuts with internal threads engage with the corresponding size of the external threads of the bolt. However, there are other forms of nuts used to suit specific requirements. For nuts, hexagonal shape is preferred to the square one, as it is easy to tighten even in a limited space. This is because, with only one-sixth of a turn, the spanner can be reintroduced in the same position. However, square nuts are used when frequent loosening and tightening is required. The sharp corners on the head of bolts and nuts are removed by chamfering. Empirical portions of hexagonal and square head bolt & nut detail proportion Nominal diameter d = size of bolt or nut, mm Width across flats s = 1.5d+3 mm Width across corners e = 2d Thickness of bolt head k = 0.8d Thickness of nut, n = 0.9d Root diameter, d1 = d - (2 ? depth of thread) Length of the bolt L = as specified Thread length b = 2d+6mm (for l<150mm) = 2d+12mm (for l>150mm) Chamfer of bolt end, Z = (depth of thread ? 45 0 ) or =0.1d Chamfer angle of bolt head & nut 30 0
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
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College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
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PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
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To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
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ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
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Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
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Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
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The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
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The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
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1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
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Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power
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Terms and Nomenclature
1. Crest: It is the peak edge of a screw thread that connects the adjacent flanks at the top. 2. Root: It is the bottom edge of the thread that connects the adjacent flanks at the bottom. 3. Flank or side: It is the straight portion of the surface, on either side of the screw thread. 4. Angle of the thread: It is the angle included between the sides of two adjacent threads measured on an axial plane. 5. Depth of the thread: It is the distance between the crest and the root measured at Right angle to the axis. It is equal to half the difference between the outer diameter and the core diameter. 6. Major diameter or outside diameter: It is the diameter of the imaginary coaxial cylinder, which would bind the crests of an external or internal thread. 7. Minor or core or root diameter: It is the diameter of the imaginary coaxial cylinder; this would bind the roots of an external thread or of an internal thread. 8. Pitch diameter: It is the diameter of the imaginary coaxial cylinder that can be passed so as to cut the thread, that the width of the cut thread will be equal to the Width of the groove. 9. Pitch: It is the axial distance between a point on one thread and the corresponding Point on the next thread. It may be indicated as the distance from crest or from root of two adjacent threads. 10. Lead: It is the distance measured parallel to the axis from a point on a thread to the corresponding point on the same thread for one complete revolution. In other words, it is axial distance a screw advances in one revolution. 11. External thread: It is the thread on the outside surface of a member such as bolt, studs or screw. 12. Internal thread: It is the thread on the inside surface of a member such as nut or threaded hole. 13. Right hand thread: Right hand thread if turned clockwise direction advances into a threaded hole. It abbreviated as RH. 14. Left hand thread: Left hand thread if turned anticlockwise direction advances into a threaded hole. It abbreviated as LH.
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V- THREADS British standard whit worth thread (BSW) This thread was introduced by Sir Joseph whit worth, and was standardized as British standard thread. It has a thread angle of 55 degree and is rounded equally at crest and roots. British Association threads (B.A Threads) The angle between flanks is 47.5 degree. These threads are to supplement BSW and have fine pitches. They are used on screws for precision work. American standard threads (or) sellers thread The thread angle is 60 degree and both the crests and roots are kept flat. The sellers thread has been in use in USA and Canada. Unified screw threads The countries UK, U.S.A and Canada came to an arrangement for a common screw thread system with the included angle of 60 degree and designated as unified screw thread in the year 1949. The thread on the bolt is rounded off at the crest and root and the thread in the nut is rounded off at the root but the crest is left flat. This thread is very important in the motor and aeroplane industries and in chemical engineering. Unified thread can be either coarse (UNC) or fine (UNF) and unified national extra fine (UEF). ISO Metric Thread This is Indian standard thread for ISO (International Standard Organization). The included angle is 60 0 and the crests are flat and roots are round. Metric threads are grouped into diameter pitch combination differentiated by the pitch applied to specific diameters. There are coarse, constant, fine pitch series available. ISO metric threads are defined by nominal size (Basic major diameter) and pitch both expressed in millimeters. for example, a 10mm diameter, 1.25 pitches is expressed as M10?1.25. SQUARE THREADS Basic square thread The sides of these threads are normal to the axis and parallel to each other. The depth and the thickness of the thread are equal to half pitch. A square thread is designated by the letter SQ followed by nominal diameter pitch. For example a square thread of nominal diameter 30mm and pitch 6mm is designated as SQ 30?6. Acme Thread It is a modified form of square thread. It is easier to cut and is much stronger than square thread. It has a 29 0
thread angle. This inclined sides of the thread facilitate quick and early engagement and disengagement. It is used for power screws like lead screw of lathe, jackscrews, bench vices and valve operating screws.
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Buttress Thread The profile of this thread is a combination of square and V- threads. It combines the low frictional of square and ability to transmit power of square thread and the strength of V ? thread. It is used to transmit load in uni-direction. These threads are used in screw press, vices.
Knuckle Thread It is also a modification of square thread. The sharp corners of square thread are rounded off. This thread is used where heavy wear rough use is expected. The thread can be rolled or cast easily. It is used in railway carriage coupling screws, light bulbs and sockets, bottle caps etc and also objects made of brittle materials as glass, plastic, porcelains etc.
Types of thread profiles
Keys Keys are machine elements used to prevent relative rotational movement between a shaft and the parts mounted on it, such as pulleys, gears, wheels, couplings, etc. for making the joint, keyways are cut on the surface of the shaft and in the hub of the part to be mounted. After positioning the part on the shaft such that, both the keyways are properly aligned, the key is driven from the end, resulting in a firm joint. For mounting a part at any intermediate location on the shaft, first the key is firmly placed in the keyways of the shaft and then the part to be mounted is slid from one end of the shaft, till it is fully engaged with the key. Keys are classified into three types. 1. Saddle keys I. flat saddle key II. hollow saddle key
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2. Sunk keys I. taper sunk keys II. parallel sunk keys III. woodruff keys 3. Round keys
Types of keys
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Bolt and nuts A bolt and nut in combination is a fastening device used to hold two parts together. The body of the bolt, called shank is cylindrical in form, the head; square or hexagonal in shape, is formed by forging. Screw threads are cut on the other end of the shank. Nuts in general are square or hexagonal in shape. The nuts with internal threads engage with the corresponding size of the external threads of the bolt. However, there are other forms of nuts used to suit specific requirements. For nuts, hexagonal shape is preferred to the square one, as it is easy to tighten even in a limited space. This is because, with only one-sixth of a turn, the spanner can be reintroduced in the same position. However, square nuts are used when frequent loosening and tightening is required. The sharp corners on the head of bolts and nuts are removed by chamfering. Empirical portions of hexagonal and square head bolt & nut detail proportion Nominal diameter d = size of bolt or nut, mm Width across flats s = 1.5d+3 mm Width across corners e = 2d Thickness of bolt head k = 0.8d Thickness of nut, n = 0.9d Root diameter, d1 = d - (2 ? depth of thread) Length of the bolt L = as specified Thread length b = 2d+6mm (for l<150mm) = 2d+12mm (for l>150mm) Chamfer of bolt end, Z = (depth of thread ? 45 0 ) or =0.1d Chamfer angle of bolt head & nut 30 0
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1.5 Limits, fits and tolerances Limit System Following are some of the terms used in the limit system: Tolerance: The permissible variation of a size is called tolerance. It is the difference between the maximum and minimum permissible limits of the given size. If the variation is provided on one side of the basic size, it is termed as unilateral tolerance. Similarly, if the variation is provided on both sides of the basic size, it is known as bilateral tolerance. Limits: The two extreme permissible sizes between which the actual size is contained are called limits. The maximum size is called the upper limit and the minimum size is called the lower limit. Deviation: It is the algebraic difference between a size (actual, maximum, etc.) and the corresponding basic size. Actual deviation: It is the algebraic difference between the actual size and the corresponding basic size. Upper deviation: It is the algebraic difference between the maximum limit of the size and the corresponding basic size. Lower deviation: It is the algebraic difference between the minimum limit of the size and the corresponding basic size. Allowance: It is the dimensional difference between the maximum material limits of the mating parts, intentionally provided to obtain the desired class of fit. If the allowance is positive, it will result in minimum clearance between the mating parts and if the allowance is negative, it will result in maximum interference. Basic Size: It is determined solely from design calculations. If the strength and stiffness requirements need a 50mm diameter shaft, then 50mm is the basic shaft size. If it has to fit into a hole, then 50 mm is the basic size of the hole. Here, the two limit dimensions of the shaft are deviating in the negative direction with respect to the basic size and those of the hole in the positive direction. The line corresponding to the basic size is called the zero line or line of zero deviation.
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
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PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
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To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
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ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
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Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
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Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
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The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
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The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
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1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
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Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power
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Terms and Nomenclature
1. Crest: It is the peak edge of a screw thread that connects the adjacent flanks at the top. 2. Root: It is the bottom edge of the thread that connects the adjacent flanks at the bottom. 3. Flank or side: It is the straight portion of the surface, on either side of the screw thread. 4. Angle of the thread: It is the angle included between the sides of two adjacent threads measured on an axial plane. 5. Depth of the thread: It is the distance between the crest and the root measured at Right angle to the axis. It is equal to half the difference between the outer diameter and the core diameter. 6. Major diameter or outside diameter: It is the diameter of the imaginary coaxial cylinder, which would bind the crests of an external or internal thread. 7. Minor or core or root diameter: It is the diameter of the imaginary coaxial cylinder; this would bind the roots of an external thread or of an internal thread. 8. Pitch diameter: It is the diameter of the imaginary coaxial cylinder that can be passed so as to cut the thread, that the width of the cut thread will be equal to the Width of the groove. 9. Pitch: It is the axial distance between a point on one thread and the corresponding Point on the next thread. It may be indicated as the distance from crest or from root of two adjacent threads. 10. Lead: It is the distance measured parallel to the axis from a point on a thread to the corresponding point on the same thread for one complete revolution. In other words, it is axial distance a screw advances in one revolution. 11. External thread: It is the thread on the outside surface of a member such as bolt, studs or screw. 12. Internal thread: It is the thread on the inside surface of a member such as nut or threaded hole. 13. Right hand thread: Right hand thread if turned clockwise direction advances into a threaded hole. It abbreviated as RH. 14. Left hand thread: Left hand thread if turned anticlockwise direction advances into a threaded hole. It abbreviated as LH.
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V- THREADS British standard whit worth thread (BSW) This thread was introduced by Sir Joseph whit worth, and was standardized as British standard thread. It has a thread angle of 55 degree and is rounded equally at crest and roots. British Association threads (B.A Threads) The angle between flanks is 47.5 degree. These threads are to supplement BSW and have fine pitches. They are used on screws for precision work. American standard threads (or) sellers thread The thread angle is 60 degree and both the crests and roots are kept flat. The sellers thread has been in use in USA and Canada. Unified screw threads The countries UK, U.S.A and Canada came to an arrangement for a common screw thread system with the included angle of 60 degree and designated as unified screw thread in the year 1949. The thread on the bolt is rounded off at the crest and root and the thread in the nut is rounded off at the root but the crest is left flat. This thread is very important in the motor and aeroplane industries and in chemical engineering. Unified thread can be either coarse (UNC) or fine (UNF) and unified national extra fine (UEF). ISO Metric Thread This is Indian standard thread for ISO (International Standard Organization). The included angle is 60 0 and the crests are flat and roots are round. Metric threads are grouped into diameter pitch combination differentiated by the pitch applied to specific diameters. There are coarse, constant, fine pitch series available. ISO metric threads are defined by nominal size (Basic major diameter) and pitch both expressed in millimeters. for example, a 10mm diameter, 1.25 pitches is expressed as M10?1.25. SQUARE THREADS Basic square thread The sides of these threads are normal to the axis and parallel to each other. The depth and the thickness of the thread are equal to half pitch. A square thread is designated by the letter SQ followed by nominal diameter pitch. For example a square thread of nominal diameter 30mm and pitch 6mm is designated as SQ 30?6. Acme Thread It is a modified form of square thread. It is easier to cut and is much stronger than square thread. It has a 29 0
thread angle. This inclined sides of the thread facilitate quick and early engagement and disengagement. It is used for power screws like lead screw of lathe, jackscrews, bench vices and valve operating screws.
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Buttress Thread The profile of this thread is a combination of square and V- threads. It combines the low frictional of square and ability to transmit power of square thread and the strength of V ? thread. It is used to transmit load in uni-direction. These threads are used in screw press, vices.
Knuckle Thread It is also a modification of square thread. The sharp corners of square thread are rounded off. This thread is used where heavy wear rough use is expected. The thread can be rolled or cast easily. It is used in railway carriage coupling screws, light bulbs and sockets, bottle caps etc and also objects made of brittle materials as glass, plastic, porcelains etc.
Types of thread profiles
Keys Keys are machine elements used to prevent relative rotational movement between a shaft and the parts mounted on it, such as pulleys, gears, wheels, couplings, etc. for making the joint, keyways are cut on the surface of the shaft and in the hub of the part to be mounted. After positioning the part on the shaft such that, both the keyways are properly aligned, the key is driven from the end, resulting in a firm joint. For mounting a part at any intermediate location on the shaft, first the key is firmly placed in the keyways of the shaft and then the part to be mounted is slid from one end of the shaft, till it is fully engaged with the key. Keys are classified into three types. 1. Saddle keys I. flat saddle key II. hollow saddle key
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2. Sunk keys I. taper sunk keys II. parallel sunk keys III. woodruff keys 3. Round keys
Types of keys
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Bolt and nuts A bolt and nut in combination is a fastening device used to hold two parts together. The body of the bolt, called shank is cylindrical in form, the head; square or hexagonal in shape, is formed by forging. Screw threads are cut on the other end of the shank. Nuts in general are square or hexagonal in shape. The nuts with internal threads engage with the corresponding size of the external threads of the bolt. However, there are other forms of nuts used to suit specific requirements. For nuts, hexagonal shape is preferred to the square one, as it is easy to tighten even in a limited space. This is because, with only one-sixth of a turn, the spanner can be reintroduced in the same position. However, square nuts are used when frequent loosening and tightening is required. The sharp corners on the head of bolts and nuts are removed by chamfering. Empirical portions of hexagonal and square head bolt & nut detail proportion Nominal diameter d = size of bolt or nut, mm Width across flats s = 1.5d+3 mm Width across corners e = 2d Thickness of bolt head k = 0.8d Thickness of nut, n = 0.9d Root diameter, d1 = d - (2 ? depth of thread) Length of the bolt L = as specified Thread length b = 2d+6mm (for l<150mm) = 2d+12mm (for l>150mm) Chamfer of bolt end, Z = (depth of thread ? 45 0 ) or =0.1d Chamfer angle of bolt head & nut 30 0
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1.5 Limits, fits and tolerances Limit System Following are some of the terms used in the limit system: Tolerance: The permissible variation of a size is called tolerance. It is the difference between the maximum and minimum permissible limits of the given size. If the variation is provided on one side of the basic size, it is termed as unilateral tolerance. Similarly, if the variation is provided on both sides of the basic size, it is known as bilateral tolerance. Limits: The two extreme permissible sizes between which the actual size is contained are called limits. The maximum size is called the upper limit and the minimum size is called the lower limit. Deviation: It is the algebraic difference between a size (actual, maximum, etc.) and the corresponding basic size. Actual deviation: It is the algebraic difference between the actual size and the corresponding basic size. Upper deviation: It is the algebraic difference between the maximum limit of the size and the corresponding basic size. Lower deviation: It is the algebraic difference between the minimum limit of the size and the corresponding basic size. Allowance: It is the dimensional difference between the maximum material limits of the mating parts, intentionally provided to obtain the desired class of fit. If the allowance is positive, it will result in minimum clearance between the mating parts and if the allowance is negative, it will result in maximum interference. Basic Size: It is determined solely from design calculations. If the strength and stiffness requirements need a 50mm diameter shaft, then 50mm is the basic shaft size. If it has to fit into a hole, then 50 mm is the basic size of the hole. Here, the two limit dimensions of the shaft are deviating in the negative direction with respect to the basic size and those of the hole in the positive direction. The line corresponding to the basic size is called the zero line or line of zero deviation.
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Fits The relation between two mating parts is known as a fit. Depending upon the actual limits of the hole or shaft sizes, fits may be classified as clearance fit, transition fit and interference fit.
Clearance Fit: It is a fit that gives a clearance between the two mating parts. minimum clearance: It is the difference between the minimum size of the hole and the maximum size of the shaft in a clearance fit. maximum clearance: It is the difference between the maximum size of the hole and the minimum size of the shaft in a clearance or transition fit. The fit between the shaft and hole in Fig. is a clearance fit that permits a minimum clearance (allowance) value of 29.95 ? 29.90 = + 0.05 mm and a maximum clearance of + 0.15 mm.
Transition Fit: This fit may result in either interference or a clearance, depending upon the actual values of the tolerance of individual parts. The shaft in Fig. may be either smaller or larger than the hole and still be within the prescribed tolerances. It results in a clearance fit, when shaft diameter is 29.95 and hole diameter is 30.05 (+ 0.10 mm) and interference fit, when shaft diameter is 30.00 and hole diameter 29.95 (? 0.05 mm).
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
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PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
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To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
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ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
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Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
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Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
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The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
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The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
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1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
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Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power
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Terms and Nomenclature
1. Crest: It is the peak edge of a screw thread that connects the adjacent flanks at the top. 2. Root: It is the bottom edge of the thread that connects the adjacent flanks at the bottom. 3. Flank or side: It is the straight portion of the surface, on either side of the screw thread. 4. Angle of the thread: It is the angle included between the sides of two adjacent threads measured on an axial plane. 5. Depth of the thread: It is the distance between the crest and the root measured at Right angle to the axis. It is equal to half the difference between the outer diameter and the core diameter. 6. Major diameter or outside diameter: It is the diameter of the imaginary coaxial cylinder, which would bind the crests of an external or internal thread. 7. Minor or core or root diameter: It is the diameter of the imaginary coaxial cylinder; this would bind the roots of an external thread or of an internal thread. 8. Pitch diameter: It is the diameter of the imaginary coaxial cylinder that can be passed so as to cut the thread, that the width of the cut thread will be equal to the Width of the groove. 9. Pitch: It is the axial distance between a point on one thread and the corresponding Point on the next thread. It may be indicated as the distance from crest or from root of two adjacent threads. 10. Lead: It is the distance measured parallel to the axis from a point on a thread to the corresponding point on the same thread for one complete revolution. In other words, it is axial distance a screw advances in one revolution. 11. External thread: It is the thread on the outside surface of a member such as bolt, studs or screw. 12. Internal thread: It is the thread on the inside surface of a member such as nut or threaded hole. 13. Right hand thread: Right hand thread if turned clockwise direction advances into a threaded hole. It abbreviated as RH. 14. Left hand thread: Left hand thread if turned anticlockwise direction advances into a threaded hole. It abbreviated as LH.
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V- THREADS British standard whit worth thread (BSW) This thread was introduced by Sir Joseph whit worth, and was standardized as British standard thread. It has a thread angle of 55 degree and is rounded equally at crest and roots. British Association threads (B.A Threads) The angle between flanks is 47.5 degree. These threads are to supplement BSW and have fine pitches. They are used on screws for precision work. American standard threads (or) sellers thread The thread angle is 60 degree and both the crests and roots are kept flat. The sellers thread has been in use in USA and Canada. Unified screw threads The countries UK, U.S.A and Canada came to an arrangement for a common screw thread system with the included angle of 60 degree and designated as unified screw thread in the year 1949. The thread on the bolt is rounded off at the crest and root and the thread in the nut is rounded off at the root but the crest is left flat. This thread is very important in the motor and aeroplane industries and in chemical engineering. Unified thread can be either coarse (UNC) or fine (UNF) and unified national extra fine (UEF). ISO Metric Thread This is Indian standard thread for ISO (International Standard Organization). The included angle is 60 0 and the crests are flat and roots are round. Metric threads are grouped into diameter pitch combination differentiated by the pitch applied to specific diameters. There are coarse, constant, fine pitch series available. ISO metric threads are defined by nominal size (Basic major diameter) and pitch both expressed in millimeters. for example, a 10mm diameter, 1.25 pitches is expressed as M10?1.25. SQUARE THREADS Basic square thread The sides of these threads are normal to the axis and parallel to each other. The depth and the thickness of the thread are equal to half pitch. A square thread is designated by the letter SQ followed by nominal diameter pitch. For example a square thread of nominal diameter 30mm and pitch 6mm is designated as SQ 30?6. Acme Thread It is a modified form of square thread. It is easier to cut and is much stronger than square thread. It has a 29 0
thread angle. This inclined sides of the thread facilitate quick and early engagement and disengagement. It is used for power screws like lead screw of lathe, jackscrews, bench vices and valve operating screws.
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Buttress Thread The profile of this thread is a combination of square and V- threads. It combines the low frictional of square and ability to transmit power of square thread and the strength of V ? thread. It is used to transmit load in uni-direction. These threads are used in screw press, vices.
Knuckle Thread It is also a modification of square thread. The sharp corners of square thread are rounded off. This thread is used where heavy wear rough use is expected. The thread can be rolled or cast easily. It is used in railway carriage coupling screws, light bulbs and sockets, bottle caps etc and also objects made of brittle materials as glass, plastic, porcelains etc.
Types of thread profiles
Keys Keys are machine elements used to prevent relative rotational movement between a shaft and the parts mounted on it, such as pulleys, gears, wheels, couplings, etc. for making the joint, keyways are cut on the surface of the shaft and in the hub of the part to be mounted. After positioning the part on the shaft such that, both the keyways are properly aligned, the key is driven from the end, resulting in a firm joint. For mounting a part at any intermediate location on the shaft, first the key is firmly placed in the keyways of the shaft and then the part to be mounted is slid from one end of the shaft, till it is fully engaged with the key. Keys are classified into three types. 1. Saddle keys I. flat saddle key II. hollow saddle key
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2. Sunk keys I. taper sunk keys II. parallel sunk keys III. woodruff keys 3. Round keys
Types of keys
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Bolt and nuts A bolt and nut in combination is a fastening device used to hold two parts together. The body of the bolt, called shank is cylindrical in form, the head; square or hexagonal in shape, is formed by forging. Screw threads are cut on the other end of the shank. Nuts in general are square or hexagonal in shape. The nuts with internal threads engage with the corresponding size of the external threads of the bolt. However, there are other forms of nuts used to suit specific requirements. For nuts, hexagonal shape is preferred to the square one, as it is easy to tighten even in a limited space. This is because, with only one-sixth of a turn, the spanner can be reintroduced in the same position. However, square nuts are used when frequent loosening and tightening is required. The sharp corners on the head of bolts and nuts are removed by chamfering. Empirical portions of hexagonal and square head bolt & nut detail proportion Nominal diameter d = size of bolt or nut, mm Width across flats s = 1.5d+3 mm Width across corners e = 2d Thickness of bolt head k = 0.8d Thickness of nut, n = 0.9d Root diameter, d1 = d - (2 ? depth of thread) Length of the bolt L = as specified Thread length b = 2d+6mm (for l<150mm) = 2d+12mm (for l>150mm) Chamfer of bolt end, Z = (depth of thread ? 45 0 ) or =0.1d Chamfer angle of bolt head & nut 30 0
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1.5 Limits, fits and tolerances Limit System Following are some of the terms used in the limit system: Tolerance: The permissible variation of a size is called tolerance. It is the difference between the maximum and minimum permissible limits of the given size. If the variation is provided on one side of the basic size, it is termed as unilateral tolerance. Similarly, if the variation is provided on both sides of the basic size, it is known as bilateral tolerance. Limits: The two extreme permissible sizes between which the actual size is contained are called limits. The maximum size is called the upper limit and the minimum size is called the lower limit. Deviation: It is the algebraic difference between a size (actual, maximum, etc.) and the corresponding basic size. Actual deviation: It is the algebraic difference between the actual size and the corresponding basic size. Upper deviation: It is the algebraic difference between the maximum limit of the size and the corresponding basic size. Lower deviation: It is the algebraic difference between the minimum limit of the size and the corresponding basic size. Allowance: It is the dimensional difference between the maximum material limits of the mating parts, intentionally provided to obtain the desired class of fit. If the allowance is positive, it will result in minimum clearance between the mating parts and if the allowance is negative, it will result in maximum interference. Basic Size: It is determined solely from design calculations. If the strength and stiffness requirements need a 50mm diameter shaft, then 50mm is the basic shaft size. If it has to fit into a hole, then 50 mm is the basic size of the hole. Here, the two limit dimensions of the shaft are deviating in the negative direction with respect to the basic size and those of the hole in the positive direction. The line corresponding to the basic size is called the zero line or line of zero deviation.
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Fits The relation between two mating parts is known as a fit. Depending upon the actual limits of the hole or shaft sizes, fits may be classified as clearance fit, transition fit and interference fit.
Clearance Fit: It is a fit that gives a clearance between the two mating parts. minimum clearance: It is the difference between the minimum size of the hole and the maximum size of the shaft in a clearance fit. maximum clearance: It is the difference between the maximum size of the hole and the minimum size of the shaft in a clearance or transition fit. The fit between the shaft and hole in Fig. is a clearance fit that permits a minimum clearance (allowance) value of 29.95 ? 29.90 = + 0.05 mm and a maximum clearance of + 0.15 mm.
Transition Fit: This fit may result in either interference or a clearance, depending upon the actual values of the tolerance of individual parts. The shaft in Fig. may be either smaller or larger than the hole and still be within the prescribed tolerances. It results in a clearance fit, when shaft diameter is 29.95 and hole diameter is 30.05 (+ 0.10 mm) and interference fit, when shaft diameter is 30.00 and hole diameter 29.95 (? 0.05 mm).
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Interference fit: If the difference between the hole and shaft sizes is negative before assembly; an interference fit is obtained. minimum interference: It is the magnitude of the difference (negative) between the maximum size of the hole and the minimum size of the shaft in an interference fit before assembly. maximum interference: It is the magnitude of the difference between the minimum size of the hole and the maximum size of the shaft in an interference or a transition fit before assembly. The shaft in fig. is larger than the hole, so it requires a press fit, which has an effect similar to welding of two parts. The value of minimum interference is 30.25 ? 30.30 = ? 0.05 mm and maximum interference is 30.15 ? 30.40 = ? 0.25 mm.
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
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College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
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PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
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To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
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ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
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Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
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Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
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The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
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The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
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1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
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Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power
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Terms and Nomenclature
1. Crest: It is the peak edge of a screw thread that connects the adjacent flanks at the top. 2. Root: It is the bottom edge of the thread that connects the adjacent flanks at the bottom. 3. Flank or side: It is the straight portion of the surface, on either side of the screw thread. 4. Angle of the thread: It is the angle included between the sides of two adjacent threads measured on an axial plane. 5. Depth of the thread: It is the distance between the crest and the root measured at Right angle to the axis. It is equal to half the difference between the outer diameter and the core diameter. 6. Major diameter or outside diameter: It is the diameter of the imaginary coaxial cylinder, which would bind the crests of an external or internal thread. 7. Minor or core or root diameter: It is the diameter of the imaginary coaxial cylinder; this would bind the roots of an external thread or of an internal thread. 8. Pitch diameter: It is the diameter of the imaginary coaxial cylinder that can be passed so as to cut the thread, that the width of the cut thread will be equal to the Width of the groove. 9. Pitch: It is the axial distance between a point on one thread and the corresponding Point on the next thread. It may be indicated as the distance from crest or from root of two adjacent threads. 10. Lead: It is the distance measured parallel to the axis from a point on a thread to the corresponding point on the same thread for one complete revolution. In other words, it is axial distance a screw advances in one revolution. 11. External thread: It is the thread on the outside surface of a member such as bolt, studs or screw. 12. Internal thread: It is the thread on the inside surface of a member such as nut or threaded hole. 13. Right hand thread: Right hand thread if turned clockwise direction advances into a threaded hole. It abbreviated as RH. 14. Left hand thread: Left hand thread if turned anticlockwise direction advances into a threaded hole. It abbreviated as LH.
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V- THREADS British standard whit worth thread (BSW) This thread was introduced by Sir Joseph whit worth, and was standardized as British standard thread. It has a thread angle of 55 degree and is rounded equally at crest and roots. British Association threads (B.A Threads) The angle between flanks is 47.5 degree. These threads are to supplement BSW and have fine pitches. They are used on screws for precision work. American standard threads (or) sellers thread The thread angle is 60 degree and both the crests and roots are kept flat. The sellers thread has been in use in USA and Canada. Unified screw threads The countries UK, U.S.A and Canada came to an arrangement for a common screw thread system with the included angle of 60 degree and designated as unified screw thread in the year 1949. The thread on the bolt is rounded off at the crest and root and the thread in the nut is rounded off at the root but the crest is left flat. This thread is very important in the motor and aeroplane industries and in chemical engineering. Unified thread can be either coarse (UNC) or fine (UNF) and unified national extra fine (UEF). ISO Metric Thread This is Indian standard thread for ISO (International Standard Organization). The included angle is 60 0 and the crests are flat and roots are round. Metric threads are grouped into diameter pitch combination differentiated by the pitch applied to specific diameters. There are coarse, constant, fine pitch series available. ISO metric threads are defined by nominal size (Basic major diameter) and pitch both expressed in millimeters. for example, a 10mm diameter, 1.25 pitches is expressed as M10?1.25. SQUARE THREADS Basic square thread The sides of these threads are normal to the axis and parallel to each other. The depth and the thickness of the thread are equal to half pitch. A square thread is designated by the letter SQ followed by nominal diameter pitch. For example a square thread of nominal diameter 30mm and pitch 6mm is designated as SQ 30?6. Acme Thread It is a modified form of square thread. It is easier to cut and is much stronger than square thread. It has a 29 0
thread angle. This inclined sides of the thread facilitate quick and early engagement and disengagement. It is used for power screws like lead screw of lathe, jackscrews, bench vices and valve operating screws.
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Buttress Thread The profile of this thread is a combination of square and V- threads. It combines the low frictional of square and ability to transmit power of square thread and the strength of V ? thread. It is used to transmit load in uni-direction. These threads are used in screw press, vices.
Knuckle Thread It is also a modification of square thread. The sharp corners of square thread are rounded off. This thread is used where heavy wear rough use is expected. The thread can be rolled or cast easily. It is used in railway carriage coupling screws, light bulbs and sockets, bottle caps etc and also objects made of brittle materials as glass, plastic, porcelains etc.
Types of thread profiles
Keys Keys are machine elements used to prevent relative rotational movement between a shaft and the parts mounted on it, such as pulleys, gears, wheels, couplings, etc. for making the joint, keyways are cut on the surface of the shaft and in the hub of the part to be mounted. After positioning the part on the shaft such that, both the keyways are properly aligned, the key is driven from the end, resulting in a firm joint. For mounting a part at any intermediate location on the shaft, first the key is firmly placed in the keyways of the shaft and then the part to be mounted is slid from one end of the shaft, till it is fully engaged with the key. Keys are classified into three types. 1. Saddle keys I. flat saddle key II. hollow saddle key
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2. Sunk keys I. taper sunk keys II. parallel sunk keys III. woodruff keys 3. Round keys
Types of keys
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Bolt and nuts A bolt and nut in combination is a fastening device used to hold two parts together. The body of the bolt, called shank is cylindrical in form, the head; square or hexagonal in shape, is formed by forging. Screw threads are cut on the other end of the shank. Nuts in general are square or hexagonal in shape. The nuts with internal threads engage with the corresponding size of the external threads of the bolt. However, there are other forms of nuts used to suit specific requirements. For nuts, hexagonal shape is preferred to the square one, as it is easy to tighten even in a limited space. This is because, with only one-sixth of a turn, the spanner can be reintroduced in the same position. However, square nuts are used when frequent loosening and tightening is required. The sharp corners on the head of bolts and nuts are removed by chamfering. Empirical portions of hexagonal and square head bolt & nut detail proportion Nominal diameter d = size of bolt or nut, mm Width across flats s = 1.5d+3 mm Width across corners e = 2d Thickness of bolt head k = 0.8d Thickness of nut, n = 0.9d Root diameter, d1 = d - (2 ? depth of thread) Length of the bolt L = as specified Thread length b = 2d+6mm (for l<150mm) = 2d+12mm (for l>150mm) Chamfer of bolt end, Z = (depth of thread ? 45 0 ) or =0.1d Chamfer angle of bolt head & nut 30 0
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1.5 Limits, fits and tolerances Limit System Following are some of the terms used in the limit system: Tolerance: The permissible variation of a size is called tolerance. It is the difference between the maximum and minimum permissible limits of the given size. If the variation is provided on one side of the basic size, it is termed as unilateral tolerance. Similarly, if the variation is provided on both sides of the basic size, it is known as bilateral tolerance. Limits: The two extreme permissible sizes between which the actual size is contained are called limits. The maximum size is called the upper limit and the minimum size is called the lower limit. Deviation: It is the algebraic difference between a size (actual, maximum, etc.) and the corresponding basic size. Actual deviation: It is the algebraic difference between the actual size and the corresponding basic size. Upper deviation: It is the algebraic difference between the maximum limit of the size and the corresponding basic size. Lower deviation: It is the algebraic difference between the minimum limit of the size and the corresponding basic size. Allowance: It is the dimensional difference between the maximum material limits of the mating parts, intentionally provided to obtain the desired class of fit. If the allowance is positive, it will result in minimum clearance between the mating parts and if the allowance is negative, it will result in maximum interference. Basic Size: It is determined solely from design calculations. If the strength and stiffness requirements need a 50mm diameter shaft, then 50mm is the basic shaft size. If it has to fit into a hole, then 50 mm is the basic size of the hole. Here, the two limit dimensions of the shaft are deviating in the negative direction with respect to the basic size and those of the hole in the positive direction. The line corresponding to the basic size is called the zero line or line of zero deviation.
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Fits The relation between two mating parts is known as a fit. Depending upon the actual limits of the hole or shaft sizes, fits may be classified as clearance fit, transition fit and interference fit.
Clearance Fit: It is a fit that gives a clearance between the two mating parts. minimum clearance: It is the difference between the minimum size of the hole and the maximum size of the shaft in a clearance fit. maximum clearance: It is the difference between the maximum size of the hole and the minimum size of the shaft in a clearance or transition fit. The fit between the shaft and hole in Fig. is a clearance fit that permits a minimum clearance (allowance) value of 29.95 ? 29.90 = + 0.05 mm and a maximum clearance of + 0.15 mm.
Transition Fit: This fit may result in either interference or a clearance, depending upon the actual values of the tolerance of individual parts. The shaft in Fig. may be either smaller or larger than the hole and still be within the prescribed tolerances. It results in a clearance fit, when shaft diameter is 29.95 and hole diameter is 30.05 (+ 0.10 mm) and interference fit, when shaft diameter is 30.00 and hole diameter 29.95 (? 0.05 mm).
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Interference fit: If the difference between the hole and shaft sizes is negative before assembly; an interference fit is obtained. minimum interference: It is the magnitude of the difference (negative) between the maximum size of the hole and the minimum size of the shaft in an interference fit before assembly. maximum interference: It is the magnitude of the difference between the minimum size of the hole and the maximum size of the shaft in an interference or a transition fit before assembly. The shaft in fig. is larger than the hole, so it requires a press fit, which has an effect similar to welding of two parts. The value of minimum interference is 30.25 ? 30.30 = ? 0.05 mm and maximum interference is 30.15 ? 30.40 = ? 0.25 mm.
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Schematic representation of fits:
Tolerance It is impossible to make anything to an exact size, therefore it is essential to allow a definite tolerance or permissible variation on every specified dimension. Tolerances are specified because ? Variations in properties of the material being machined introduce errors. ? The production machines themselves may have some inherent inaccuracies. ? It is impossible for an operator to make perfect settings. While setting up the tools and workpiece on the machine, some errors are likely to creep in.
Form variation: It is a variation of the actual condition of a form feature (surface, line) from geometrically ideal form. Position variation: It is a variation of the actual position of the form feature from the geometrically ideal position, with reference to another form (datum) feature. Geometrical tolerance: Geometrical tolerance is defined as the maximum permissible overall variation of form or position of a feature. FirstRanker.com - FirstRanker's Choice
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DEPARTMENT OF MECHANICAL ENGINEERING
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
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College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
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PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
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To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
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ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
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Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
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Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
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The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
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The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
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1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
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Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power
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Terms and Nomenclature
1. Crest: It is the peak edge of a screw thread that connects the adjacent flanks at the top. 2. Root: It is the bottom edge of the thread that connects the adjacent flanks at the bottom. 3. Flank or side: It is the straight portion of the surface, on either side of the screw thread. 4. Angle of the thread: It is the angle included between the sides of two adjacent threads measured on an axial plane. 5. Depth of the thread: It is the distance between the crest and the root measured at Right angle to the axis. It is equal to half the difference between the outer diameter and the core diameter. 6. Major diameter or outside diameter: It is the diameter of the imaginary coaxial cylinder, which would bind the crests of an external or internal thread. 7. Minor or core or root diameter: It is the diameter of the imaginary coaxial cylinder; this would bind the roots of an external thread or of an internal thread. 8. Pitch diameter: It is the diameter of the imaginary coaxial cylinder that can be passed so as to cut the thread, that the width of the cut thread will be equal to the Width of the groove. 9. Pitch: It is the axial distance between a point on one thread and the corresponding Point on the next thread. It may be indicated as the distance from crest or from root of two adjacent threads. 10. Lead: It is the distance measured parallel to the axis from a point on a thread to the corresponding point on the same thread for one complete revolution. In other words, it is axial distance a screw advances in one revolution. 11. External thread: It is the thread on the outside surface of a member such as bolt, studs or screw. 12. Internal thread: It is the thread on the inside surface of a member such as nut or threaded hole. 13. Right hand thread: Right hand thread if turned clockwise direction advances into a threaded hole. It abbreviated as RH. 14. Left hand thread: Left hand thread if turned anticlockwise direction advances into a threaded hole. It abbreviated as LH.
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V- THREADS British standard whit worth thread (BSW) This thread was introduced by Sir Joseph whit worth, and was standardized as British standard thread. It has a thread angle of 55 degree and is rounded equally at crest and roots. British Association threads (B.A Threads) The angle between flanks is 47.5 degree. These threads are to supplement BSW and have fine pitches. They are used on screws for precision work. American standard threads (or) sellers thread The thread angle is 60 degree and both the crests and roots are kept flat. The sellers thread has been in use in USA and Canada. Unified screw threads The countries UK, U.S.A and Canada came to an arrangement for a common screw thread system with the included angle of 60 degree and designated as unified screw thread in the year 1949. The thread on the bolt is rounded off at the crest and root and the thread in the nut is rounded off at the root but the crest is left flat. This thread is very important in the motor and aeroplane industries and in chemical engineering. Unified thread can be either coarse (UNC) or fine (UNF) and unified national extra fine (UEF). ISO Metric Thread This is Indian standard thread for ISO (International Standard Organization). The included angle is 60 0 and the crests are flat and roots are round. Metric threads are grouped into diameter pitch combination differentiated by the pitch applied to specific diameters. There are coarse, constant, fine pitch series available. ISO metric threads are defined by nominal size (Basic major diameter) and pitch both expressed in millimeters. for example, a 10mm diameter, 1.25 pitches is expressed as M10?1.25. SQUARE THREADS Basic square thread The sides of these threads are normal to the axis and parallel to each other. The depth and the thickness of the thread are equal to half pitch. A square thread is designated by the letter SQ followed by nominal diameter pitch. For example a square thread of nominal diameter 30mm and pitch 6mm is designated as SQ 30?6. Acme Thread It is a modified form of square thread. It is easier to cut and is much stronger than square thread. It has a 29 0
thread angle. This inclined sides of the thread facilitate quick and early engagement and disengagement. It is used for power screws like lead screw of lathe, jackscrews, bench vices and valve operating screws.
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Buttress Thread The profile of this thread is a combination of square and V- threads. It combines the low frictional of square and ability to transmit power of square thread and the strength of V ? thread. It is used to transmit load in uni-direction. These threads are used in screw press, vices.
Knuckle Thread It is also a modification of square thread. The sharp corners of square thread are rounded off. This thread is used where heavy wear rough use is expected. The thread can be rolled or cast easily. It is used in railway carriage coupling screws, light bulbs and sockets, bottle caps etc and also objects made of brittle materials as glass, plastic, porcelains etc.
Types of thread profiles
Keys Keys are machine elements used to prevent relative rotational movement between a shaft and the parts mounted on it, such as pulleys, gears, wheels, couplings, etc. for making the joint, keyways are cut on the surface of the shaft and in the hub of the part to be mounted. After positioning the part on the shaft such that, both the keyways are properly aligned, the key is driven from the end, resulting in a firm joint. For mounting a part at any intermediate location on the shaft, first the key is firmly placed in the keyways of the shaft and then the part to be mounted is slid from one end of the shaft, till it is fully engaged with the key. Keys are classified into three types. 1. Saddle keys I. flat saddle key II. hollow saddle key
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2. Sunk keys I. taper sunk keys II. parallel sunk keys III. woodruff keys 3. Round keys
Types of keys
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Bolt and nuts A bolt and nut in combination is a fastening device used to hold two parts together. The body of the bolt, called shank is cylindrical in form, the head; square or hexagonal in shape, is formed by forging. Screw threads are cut on the other end of the shank. Nuts in general are square or hexagonal in shape. The nuts with internal threads engage with the corresponding size of the external threads of the bolt. However, there are other forms of nuts used to suit specific requirements. For nuts, hexagonal shape is preferred to the square one, as it is easy to tighten even in a limited space. This is because, with only one-sixth of a turn, the spanner can be reintroduced in the same position. However, square nuts are used when frequent loosening and tightening is required. The sharp corners on the head of bolts and nuts are removed by chamfering. Empirical portions of hexagonal and square head bolt & nut detail proportion Nominal diameter d = size of bolt or nut, mm Width across flats s = 1.5d+3 mm Width across corners e = 2d Thickness of bolt head k = 0.8d Thickness of nut, n = 0.9d Root diameter, d1 = d - (2 ? depth of thread) Length of the bolt L = as specified Thread length b = 2d+6mm (for l<150mm) = 2d+12mm (for l>150mm) Chamfer of bolt end, Z = (depth of thread ? 45 0 ) or =0.1d Chamfer angle of bolt head & nut 30 0
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1.5 Limits, fits and tolerances Limit System Following are some of the terms used in the limit system: Tolerance: The permissible variation of a size is called tolerance. It is the difference between the maximum and minimum permissible limits of the given size. If the variation is provided on one side of the basic size, it is termed as unilateral tolerance. Similarly, if the variation is provided on both sides of the basic size, it is known as bilateral tolerance. Limits: The two extreme permissible sizes between which the actual size is contained are called limits. The maximum size is called the upper limit and the minimum size is called the lower limit. Deviation: It is the algebraic difference between a size (actual, maximum, etc.) and the corresponding basic size. Actual deviation: It is the algebraic difference between the actual size and the corresponding basic size. Upper deviation: It is the algebraic difference between the maximum limit of the size and the corresponding basic size. Lower deviation: It is the algebraic difference between the minimum limit of the size and the corresponding basic size. Allowance: It is the dimensional difference between the maximum material limits of the mating parts, intentionally provided to obtain the desired class of fit. If the allowance is positive, it will result in minimum clearance between the mating parts and if the allowance is negative, it will result in maximum interference. Basic Size: It is determined solely from design calculations. If the strength and stiffness requirements need a 50mm diameter shaft, then 50mm is the basic shaft size. If it has to fit into a hole, then 50 mm is the basic size of the hole. Here, the two limit dimensions of the shaft are deviating in the negative direction with respect to the basic size and those of the hole in the positive direction. The line corresponding to the basic size is called the zero line or line of zero deviation.
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Fits The relation between two mating parts is known as a fit. Depending upon the actual limits of the hole or shaft sizes, fits may be classified as clearance fit, transition fit and interference fit.
Clearance Fit: It is a fit that gives a clearance between the two mating parts. minimum clearance: It is the difference between the minimum size of the hole and the maximum size of the shaft in a clearance fit. maximum clearance: It is the difference between the maximum size of the hole and the minimum size of the shaft in a clearance or transition fit. The fit between the shaft and hole in Fig. is a clearance fit that permits a minimum clearance (allowance) value of 29.95 ? 29.90 = + 0.05 mm and a maximum clearance of + 0.15 mm.
Transition Fit: This fit may result in either interference or a clearance, depending upon the actual values of the tolerance of individual parts. The shaft in Fig. may be either smaller or larger than the hole and still be within the prescribed tolerances. It results in a clearance fit, when shaft diameter is 29.95 and hole diameter is 30.05 (+ 0.10 mm) and interference fit, when shaft diameter is 30.00 and hole diameter 29.95 (? 0.05 mm).
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Interference fit: If the difference between the hole and shaft sizes is negative before assembly; an interference fit is obtained. minimum interference: It is the magnitude of the difference (negative) between the maximum size of the hole and the minimum size of the shaft in an interference fit before assembly. maximum interference: It is the magnitude of the difference between the minimum size of the hole and the maximum size of the shaft in an interference or a transition fit before assembly. The shaft in fig. is larger than the hole, so it requires a press fit, which has an effect similar to welding of two parts. The value of minimum interference is 30.25 ? 30.30 = ? 0.05 mm and maximum interference is 30.15 ? 30.40 = ? 0.25 mm.
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Schematic representation of fits:
Tolerance It is impossible to make anything to an exact size, therefore it is essential to allow a definite tolerance or permissible variation on every specified dimension. Tolerances are specified because ? Variations in properties of the material being machined introduce errors. ? The production machines themselves may have some inherent inaccuracies. ? It is impossible for an operator to make perfect settings. While setting up the tools and workpiece on the machine, some errors are likely to creep in.
Form variation: It is a variation of the actual condition of a form feature (surface, line) from geometrically ideal form. Position variation: It is a variation of the actual position of the form feature from the geometrically ideal position, with reference to another form (datum) feature. Geometrical tolerance: Geometrical tolerance is defined as the maximum permissible overall variation of form or position of a feature.
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Geometrical tolerances are used, (i) to specify the required accuracy in controlling the form of a feature, (ii) to ensure correct functional positioning of the feature, (iii) to ensure the interchangeability of components, and (iv) to facilitate the assembly of mating components. Tolerance zone: It is an imaginary area or volume within which the controlled feature of the manufactured component must be completely contained Datum: It is a theoretically exact geometric reference (such as axes, planes, straight lines, etc.) to which the tolerance features are related. Datum feature: A datum feature is a feature of a part, such as an edge, surface, or a hole, which forms the basis for a datum or is used to establish its location
Datum triangle: The datums are indicated by a leader line, terminating in a filled or an open triangle. Datum letter: To identify a datum for reference purposes, a capital letter is enclosed in a frame, connected to the datum triangle.
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
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College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
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PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
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To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
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ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
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Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
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Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
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The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
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The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
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1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
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Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power
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Terms and Nomenclature
1. Crest: It is the peak edge of a screw thread that connects the adjacent flanks at the top. 2. Root: It is the bottom edge of the thread that connects the adjacent flanks at the bottom. 3. Flank or side: It is the straight portion of the surface, on either side of the screw thread. 4. Angle of the thread: It is the angle included between the sides of two adjacent threads measured on an axial plane. 5. Depth of the thread: It is the distance between the crest and the root measured at Right angle to the axis. It is equal to half the difference between the outer diameter and the core diameter. 6. Major diameter or outside diameter: It is the diameter of the imaginary coaxial cylinder, which would bind the crests of an external or internal thread. 7. Minor or core or root diameter: It is the diameter of the imaginary coaxial cylinder; this would bind the roots of an external thread or of an internal thread. 8. Pitch diameter: It is the diameter of the imaginary coaxial cylinder that can be passed so as to cut the thread, that the width of the cut thread will be equal to the Width of the groove. 9. Pitch: It is the axial distance between a point on one thread and the corresponding Point on the next thread. It may be indicated as the distance from crest or from root of two adjacent threads. 10. Lead: It is the distance measured parallel to the axis from a point on a thread to the corresponding point on the same thread for one complete revolution. In other words, it is axial distance a screw advances in one revolution. 11. External thread: It is the thread on the outside surface of a member such as bolt, studs or screw. 12. Internal thread: It is the thread on the inside surface of a member such as nut or threaded hole. 13. Right hand thread: Right hand thread if turned clockwise direction advances into a threaded hole. It abbreviated as RH. 14. Left hand thread: Left hand thread if turned anticlockwise direction advances into a threaded hole. It abbreviated as LH.
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V- THREADS British standard whit worth thread (BSW) This thread was introduced by Sir Joseph whit worth, and was standardized as British standard thread. It has a thread angle of 55 degree and is rounded equally at crest and roots. British Association threads (B.A Threads) The angle between flanks is 47.5 degree. These threads are to supplement BSW and have fine pitches. They are used on screws for precision work. American standard threads (or) sellers thread The thread angle is 60 degree and both the crests and roots are kept flat. The sellers thread has been in use in USA and Canada. Unified screw threads The countries UK, U.S.A and Canada came to an arrangement for a common screw thread system with the included angle of 60 degree and designated as unified screw thread in the year 1949. The thread on the bolt is rounded off at the crest and root and the thread in the nut is rounded off at the root but the crest is left flat. This thread is very important in the motor and aeroplane industries and in chemical engineering. Unified thread can be either coarse (UNC) or fine (UNF) and unified national extra fine (UEF). ISO Metric Thread This is Indian standard thread for ISO (International Standard Organization). The included angle is 60 0 and the crests are flat and roots are round. Metric threads are grouped into diameter pitch combination differentiated by the pitch applied to specific diameters. There are coarse, constant, fine pitch series available. ISO metric threads are defined by nominal size (Basic major diameter) and pitch both expressed in millimeters. for example, a 10mm diameter, 1.25 pitches is expressed as M10?1.25. SQUARE THREADS Basic square thread The sides of these threads are normal to the axis and parallel to each other. The depth and the thickness of the thread are equal to half pitch. A square thread is designated by the letter SQ followed by nominal diameter pitch. For example a square thread of nominal diameter 30mm and pitch 6mm is designated as SQ 30?6. Acme Thread It is a modified form of square thread. It is easier to cut and is much stronger than square thread. It has a 29 0
thread angle. This inclined sides of the thread facilitate quick and early engagement and disengagement. It is used for power screws like lead screw of lathe, jackscrews, bench vices and valve operating screws.
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Buttress Thread The profile of this thread is a combination of square and V- threads. It combines the low frictional of square and ability to transmit power of square thread and the strength of V ? thread. It is used to transmit load in uni-direction. These threads are used in screw press, vices.
Knuckle Thread It is also a modification of square thread. The sharp corners of square thread are rounded off. This thread is used where heavy wear rough use is expected. The thread can be rolled or cast easily. It is used in railway carriage coupling screws, light bulbs and sockets, bottle caps etc and also objects made of brittle materials as glass, plastic, porcelains etc.
Types of thread profiles
Keys Keys are machine elements used to prevent relative rotational movement between a shaft and the parts mounted on it, such as pulleys, gears, wheels, couplings, etc. for making the joint, keyways are cut on the surface of the shaft and in the hub of the part to be mounted. After positioning the part on the shaft such that, both the keyways are properly aligned, the key is driven from the end, resulting in a firm joint. For mounting a part at any intermediate location on the shaft, first the key is firmly placed in the keyways of the shaft and then the part to be mounted is slid from one end of the shaft, till it is fully engaged with the key. Keys are classified into three types. 1. Saddle keys I. flat saddle key II. hollow saddle key
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2. Sunk keys I. taper sunk keys II. parallel sunk keys III. woodruff keys 3. Round keys
Types of keys
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Bolt and nuts A bolt and nut in combination is a fastening device used to hold two parts together. The body of the bolt, called shank is cylindrical in form, the head; square or hexagonal in shape, is formed by forging. Screw threads are cut on the other end of the shank. Nuts in general are square or hexagonal in shape. The nuts with internal threads engage with the corresponding size of the external threads of the bolt. However, there are other forms of nuts used to suit specific requirements. For nuts, hexagonal shape is preferred to the square one, as it is easy to tighten even in a limited space. This is because, with only one-sixth of a turn, the spanner can be reintroduced in the same position. However, square nuts are used when frequent loosening and tightening is required. The sharp corners on the head of bolts and nuts are removed by chamfering. Empirical portions of hexagonal and square head bolt & nut detail proportion Nominal diameter d = size of bolt or nut, mm Width across flats s = 1.5d+3 mm Width across corners e = 2d Thickness of bolt head k = 0.8d Thickness of nut, n = 0.9d Root diameter, d1 = d - (2 ? depth of thread) Length of the bolt L = as specified Thread length b = 2d+6mm (for l<150mm) = 2d+12mm (for l>150mm) Chamfer of bolt end, Z = (depth of thread ? 45 0 ) or =0.1d Chamfer angle of bolt head & nut 30 0
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1.5 Limits, fits and tolerances Limit System Following are some of the terms used in the limit system: Tolerance: The permissible variation of a size is called tolerance. It is the difference between the maximum and minimum permissible limits of the given size. If the variation is provided on one side of the basic size, it is termed as unilateral tolerance. Similarly, if the variation is provided on both sides of the basic size, it is known as bilateral tolerance. Limits: The two extreme permissible sizes between which the actual size is contained are called limits. The maximum size is called the upper limit and the minimum size is called the lower limit. Deviation: It is the algebraic difference between a size (actual, maximum, etc.) and the corresponding basic size. Actual deviation: It is the algebraic difference between the actual size and the corresponding basic size. Upper deviation: It is the algebraic difference between the maximum limit of the size and the corresponding basic size. Lower deviation: It is the algebraic difference between the minimum limit of the size and the corresponding basic size. Allowance: It is the dimensional difference between the maximum material limits of the mating parts, intentionally provided to obtain the desired class of fit. If the allowance is positive, it will result in minimum clearance between the mating parts and if the allowance is negative, it will result in maximum interference. Basic Size: It is determined solely from design calculations. If the strength and stiffness requirements need a 50mm diameter shaft, then 50mm is the basic shaft size. If it has to fit into a hole, then 50 mm is the basic size of the hole. Here, the two limit dimensions of the shaft are deviating in the negative direction with respect to the basic size and those of the hole in the positive direction. The line corresponding to the basic size is called the zero line or line of zero deviation.
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Fits The relation between two mating parts is known as a fit. Depending upon the actual limits of the hole or shaft sizes, fits may be classified as clearance fit, transition fit and interference fit.
Clearance Fit: It is a fit that gives a clearance between the two mating parts. minimum clearance: It is the difference between the minimum size of the hole and the maximum size of the shaft in a clearance fit. maximum clearance: It is the difference between the maximum size of the hole and the minimum size of the shaft in a clearance or transition fit. The fit between the shaft and hole in Fig. is a clearance fit that permits a minimum clearance (allowance) value of 29.95 ? 29.90 = + 0.05 mm and a maximum clearance of + 0.15 mm.
Transition Fit: This fit may result in either interference or a clearance, depending upon the actual values of the tolerance of individual parts. The shaft in Fig. may be either smaller or larger than the hole and still be within the prescribed tolerances. It results in a clearance fit, when shaft diameter is 29.95 and hole diameter is 30.05 (+ 0.10 mm) and interference fit, when shaft diameter is 30.00 and hole diameter 29.95 (? 0.05 mm).
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Interference fit: If the difference between the hole and shaft sizes is negative before assembly; an interference fit is obtained. minimum interference: It is the magnitude of the difference (negative) between the maximum size of the hole and the minimum size of the shaft in an interference fit before assembly. maximum interference: It is the magnitude of the difference between the minimum size of the hole and the maximum size of the shaft in an interference or a transition fit before assembly. The shaft in fig. is larger than the hole, so it requires a press fit, which has an effect similar to welding of two parts. The value of minimum interference is 30.25 ? 30.30 = ? 0.05 mm and maximum interference is 30.15 ? 30.40 = ? 0.25 mm.
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Schematic representation of fits:
Tolerance It is impossible to make anything to an exact size, therefore it is essential to allow a definite tolerance or permissible variation on every specified dimension. Tolerances are specified because ? Variations in properties of the material being machined introduce errors. ? The production machines themselves may have some inherent inaccuracies. ? It is impossible for an operator to make perfect settings. While setting up the tools and workpiece on the machine, some errors are likely to creep in.
Form variation: It is a variation of the actual condition of a form feature (surface, line) from geometrically ideal form. Position variation: It is a variation of the actual position of the form feature from the geometrically ideal position, with reference to another form (datum) feature. Geometrical tolerance: Geometrical tolerance is defined as the maximum permissible overall variation of form or position of a feature.
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Geometrical tolerances are used, (i) to specify the required accuracy in controlling the form of a feature, (ii) to ensure correct functional positioning of the feature, (iii) to ensure the interchangeability of components, and (iv) to facilitate the assembly of mating components. Tolerance zone: It is an imaginary area or volume within which the controlled feature of the manufactured component must be completely contained Datum: It is a theoretically exact geometric reference (such as axes, planes, straight lines, etc.) to which the tolerance features are related. Datum feature: A datum feature is a feature of a part, such as an edge, surface, or a hole, which forms the basis for a datum or is used to establish its location
Datum triangle: The datums are indicated by a leader line, terminating in a filled or an open triangle. Datum letter: To identify a datum for reference purposes, a capital letter is enclosed in a frame, connected to the datum triangle.
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ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00
College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
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PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
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To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
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ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
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Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
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Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
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The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
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The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
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1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
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Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power
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Terms and Nomenclature
1. Crest: It is the peak edge of a screw thread that connects the adjacent flanks at the top. 2. Root: It is the bottom edge of the thread that connects the adjacent flanks at the bottom. 3. Flank or side: It is the straight portion of the surface, on either side of the screw thread. 4. Angle of the thread: It is the angle included between the sides of two adjacent threads measured on an axial plane. 5. Depth of the thread: It is the distance between the crest and the root measured at Right angle to the axis. It is equal to half the difference between the outer diameter and the core diameter. 6. Major diameter or outside diameter: It is the diameter of the imaginary coaxial cylinder, which would bind the crests of an external or internal thread. 7. Minor or core or root diameter: It is the diameter of the imaginary coaxial cylinder; this would bind the roots of an external thread or of an internal thread. 8. Pitch diameter: It is the diameter of the imaginary coaxial cylinder that can be passed so as to cut the thread, that the width of the cut thread will be equal to the Width of the groove. 9. Pitch: It is the axial distance between a point on one thread and the corresponding Point on the next thread. It may be indicated as the distance from crest or from root of two adjacent threads. 10. Lead: It is the distance measured parallel to the axis from a point on a thread to the corresponding point on the same thread for one complete revolution. In other words, it is axial distance a screw advances in one revolution. 11. External thread: It is the thread on the outside surface of a member such as bolt, studs or screw. 12. Internal thread: It is the thread on the inside surface of a member such as nut or threaded hole. 13. Right hand thread: Right hand thread if turned clockwise direction advances into a threaded hole. It abbreviated as RH. 14. Left hand thread: Left hand thread if turned anticlockwise direction advances into a threaded hole. It abbreviated as LH.
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V- THREADS British standard whit worth thread (BSW) This thread was introduced by Sir Joseph whit worth, and was standardized as British standard thread. It has a thread angle of 55 degree and is rounded equally at crest and roots. British Association threads (B.A Threads) The angle between flanks is 47.5 degree. These threads are to supplement BSW and have fine pitches. They are used on screws for precision work. American standard threads (or) sellers thread The thread angle is 60 degree and both the crests and roots are kept flat. The sellers thread has been in use in USA and Canada. Unified screw threads The countries UK, U.S.A and Canada came to an arrangement for a common screw thread system with the included angle of 60 degree and designated as unified screw thread in the year 1949. The thread on the bolt is rounded off at the crest and root and the thread in the nut is rounded off at the root but the crest is left flat. This thread is very important in the motor and aeroplane industries and in chemical engineering. Unified thread can be either coarse (UNC) or fine (UNF) and unified national extra fine (UEF). ISO Metric Thread This is Indian standard thread for ISO (International Standard Organization). The included angle is 60 0 and the crests are flat and roots are round. Metric threads are grouped into diameter pitch combination differentiated by the pitch applied to specific diameters. There are coarse, constant, fine pitch series available. ISO metric threads are defined by nominal size (Basic major diameter) and pitch both expressed in millimeters. for example, a 10mm diameter, 1.25 pitches is expressed as M10?1.25. SQUARE THREADS Basic square thread The sides of these threads are normal to the axis and parallel to each other. The depth and the thickness of the thread are equal to half pitch. A square thread is designated by the letter SQ followed by nominal diameter pitch. For example a square thread of nominal diameter 30mm and pitch 6mm is designated as SQ 30?6. Acme Thread It is a modified form of square thread. It is easier to cut and is much stronger than square thread. It has a 29 0
thread angle. This inclined sides of the thread facilitate quick and early engagement and disengagement. It is used for power screws like lead screw of lathe, jackscrews, bench vices and valve operating screws.
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Buttress Thread The profile of this thread is a combination of square and V- threads. It combines the low frictional of square and ability to transmit power of square thread and the strength of V ? thread. It is used to transmit load in uni-direction. These threads are used in screw press, vices.
Knuckle Thread It is also a modification of square thread. The sharp corners of square thread are rounded off. This thread is used where heavy wear rough use is expected. The thread can be rolled or cast easily. It is used in railway carriage coupling screws, light bulbs and sockets, bottle caps etc and also objects made of brittle materials as glass, plastic, porcelains etc.
Types of thread profiles
Keys Keys are machine elements used to prevent relative rotational movement between a shaft and the parts mounted on it, such as pulleys, gears, wheels, couplings, etc. for making the joint, keyways are cut on the surface of the shaft and in the hub of the part to be mounted. After positioning the part on the shaft such that, both the keyways are properly aligned, the key is driven from the end, resulting in a firm joint. For mounting a part at any intermediate location on the shaft, first the key is firmly placed in the keyways of the shaft and then the part to be mounted is slid from one end of the shaft, till it is fully engaged with the key. Keys are classified into three types. 1. Saddle keys I. flat saddle key II. hollow saddle key
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2. Sunk keys I. taper sunk keys II. parallel sunk keys III. woodruff keys 3. Round keys
Types of keys
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Bolt and nuts A bolt and nut in combination is a fastening device used to hold two parts together. The body of the bolt, called shank is cylindrical in form, the head; square or hexagonal in shape, is formed by forging. Screw threads are cut on the other end of the shank. Nuts in general are square or hexagonal in shape. The nuts with internal threads engage with the corresponding size of the external threads of the bolt. However, there are other forms of nuts used to suit specific requirements. For nuts, hexagonal shape is preferred to the square one, as it is easy to tighten even in a limited space. This is because, with only one-sixth of a turn, the spanner can be reintroduced in the same position. However, square nuts are used when frequent loosening and tightening is required. The sharp corners on the head of bolts and nuts are removed by chamfering. Empirical portions of hexagonal and square head bolt & nut detail proportion Nominal diameter d = size of bolt or nut, mm Width across flats s = 1.5d+3 mm Width across corners e = 2d Thickness of bolt head k = 0.8d Thickness of nut, n = 0.9d Root diameter, d1 = d - (2 ? depth of thread) Length of the bolt L = as specified Thread length b = 2d+6mm (for l<150mm) = 2d+12mm (for l>150mm) Chamfer of bolt end, Z = (depth of thread ? 45 0 ) or =0.1d Chamfer angle of bolt head & nut 30 0
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1.5 Limits, fits and tolerances Limit System Following are some of the terms used in the limit system: Tolerance: The permissible variation of a size is called tolerance. It is the difference between the maximum and minimum permissible limits of the given size. If the variation is provided on one side of the basic size, it is termed as unilateral tolerance. Similarly, if the variation is provided on both sides of the basic size, it is known as bilateral tolerance. Limits: The two extreme permissible sizes between which the actual size is contained are called limits. The maximum size is called the upper limit and the minimum size is called the lower limit. Deviation: It is the algebraic difference between a size (actual, maximum, etc.) and the corresponding basic size. Actual deviation: It is the algebraic difference between the actual size and the corresponding basic size. Upper deviation: It is the algebraic difference between the maximum limit of the size and the corresponding basic size. Lower deviation: It is the algebraic difference between the minimum limit of the size and the corresponding basic size. Allowance: It is the dimensional difference between the maximum material limits of the mating parts, intentionally provided to obtain the desired class of fit. If the allowance is positive, it will result in minimum clearance between the mating parts and if the allowance is negative, it will result in maximum interference. Basic Size: It is determined solely from design calculations. If the strength and stiffness requirements need a 50mm diameter shaft, then 50mm is the basic shaft size. If it has to fit into a hole, then 50 mm is the basic size of the hole. Here, the two limit dimensions of the shaft are deviating in the negative direction with respect to the basic size and those of the hole in the positive direction. The line corresponding to the basic size is called the zero line or line of zero deviation.
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Fits The relation between two mating parts is known as a fit. Depending upon the actual limits of the hole or shaft sizes, fits may be classified as clearance fit, transition fit and interference fit.
Clearance Fit: It is a fit that gives a clearance between the two mating parts. minimum clearance: It is the difference between the minimum size of the hole and the maximum size of the shaft in a clearance fit. maximum clearance: It is the difference between the maximum size of the hole and the minimum size of the shaft in a clearance or transition fit. The fit between the shaft and hole in Fig. is a clearance fit that permits a minimum clearance (allowance) value of 29.95 ? 29.90 = + 0.05 mm and a maximum clearance of + 0.15 mm.
Transition Fit: This fit may result in either interference or a clearance, depending upon the actual values of the tolerance of individual parts. The shaft in Fig. may be either smaller or larger than the hole and still be within the prescribed tolerances. It results in a clearance fit, when shaft diameter is 29.95 and hole diameter is 30.05 (+ 0.10 mm) and interference fit, when shaft diameter is 30.00 and hole diameter 29.95 (? 0.05 mm).
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Interference fit: If the difference between the hole and shaft sizes is negative before assembly; an interference fit is obtained. minimum interference: It is the magnitude of the difference (negative) between the maximum size of the hole and the minimum size of the shaft in an interference fit before assembly. maximum interference: It is the magnitude of the difference between the minimum size of the hole and the maximum size of the shaft in an interference or a transition fit before assembly. The shaft in fig. is larger than the hole, so it requires a press fit, which has an effect similar to welding of two parts. The value of minimum interference is 30.25 ? 30.30 = ? 0.05 mm and maximum interference is 30.15 ? 30.40 = ? 0.25 mm.
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Schematic representation of fits:
Tolerance It is impossible to make anything to an exact size, therefore it is essential to allow a definite tolerance or permissible variation on every specified dimension. Tolerances are specified because ? Variations in properties of the material being machined introduce errors. ? The production machines themselves may have some inherent inaccuracies. ? It is impossible for an operator to make perfect settings. While setting up the tools and workpiece on the machine, some errors are likely to creep in.
Form variation: It is a variation of the actual condition of a form feature (surface, line) from geometrically ideal form. Position variation: It is a variation of the actual position of the form feature from the geometrically ideal position, with reference to another form (datum) feature. Geometrical tolerance: Geometrical tolerance is defined as the maximum permissible overall variation of form or position of a feature.
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Geometrical tolerances are used, (i) to specify the required accuracy in controlling the form of a feature, (ii) to ensure correct functional positioning of the feature, (iii) to ensure the interchangeability of components, and (iv) to facilitate the assembly of mating components. Tolerance zone: It is an imaginary area or volume within which the controlled feature of the manufactured component must be completely contained Datum: It is a theoretically exact geometric reference (such as axes, planes, straight lines, etc.) to which the tolerance features are related. Datum feature: A datum feature is a feature of a part, such as an edge, surface, or a hole, which forms the basis for a datum or is used to establish its location
Datum triangle: The datums are indicated by a leader line, terminating in a filled or an open triangle. Datum letter: To identify a datum for reference purposes, a capital letter is enclosed in a frame, connected to the datum triangle.
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Expt. No.02 INTRODUCTION TO CADD CADD is an electronic tool that enables us to make quick and accurate drawings. CADD has number of advantages over drawings created on a drawing board. Electronic drawings can be modified quite easily and can be represented in a variety of formats. CADD extends its power to yet another branch of engineering called computer aided manufacturing (CAM).CADD and manufacturing program are often integrated into one system called CAD-CAM. This system import CADD drawings into CAM program to automate the manufacturing process. When the design is finalized, the drawings are brought into a CAD-CAM system that uses numerical data from the CADD drawing for actual manufacturing. There is separate category of programs called Computer Aided Engineering (CAE) that can use CADD drawing for engineering analysis. The CAE programs have a number of applications in Structural Design, Civil Engineering, Mechanical Engineering and Electrical Engineering. The Mechanical engineer can test a machine assembly and also a prototype electronic model and test it without building a physical model. We can do amazing things with CADD that we never thought possible while creating drawings with pen or pencil. The following are some of the important capabilities that make CADD a powerful tool. ? Presentations ? Flexibility in editing ? Unit and accuracy levels ? Storage and access for drawings ? Sharing CADD drawings Presentations There are a number of ready-made presentations symbols available in CADD that can be used to enhance the look of drawings. In addition to prepare impressive presentations on paper, we can use CADD to make an on-screen presentations. Advanced CADD programs ever allow us to create an animated image. Flexibility in editing CADD allows us to work with great accuracy. If we need to create highly accuracy geometric shapes, CADD is the answer. It can help avoid time-consuming mathematical calculations. Unit and accuracy level We can work with as high precession as 1/1000 th of an inch. Storage and access of drawing A computer electronic filing system has the following advantages over the traditional filing system. FirstRanker.com - FirstRanker's Choice
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DEPARTMENT OF MECHANICAL ENGINEERING
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
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College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
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PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
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To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
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ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
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Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
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Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
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The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
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The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
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1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
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Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power
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Terms and Nomenclature
1. Crest: It is the peak edge of a screw thread that connects the adjacent flanks at the top. 2. Root: It is the bottom edge of the thread that connects the adjacent flanks at the bottom. 3. Flank or side: It is the straight portion of the surface, on either side of the screw thread. 4. Angle of the thread: It is the angle included between the sides of two adjacent threads measured on an axial plane. 5. Depth of the thread: It is the distance between the crest and the root measured at Right angle to the axis. It is equal to half the difference between the outer diameter and the core diameter. 6. Major diameter or outside diameter: It is the diameter of the imaginary coaxial cylinder, which would bind the crests of an external or internal thread. 7. Minor or core or root diameter: It is the diameter of the imaginary coaxial cylinder; this would bind the roots of an external thread or of an internal thread. 8. Pitch diameter: It is the diameter of the imaginary coaxial cylinder that can be passed so as to cut the thread, that the width of the cut thread will be equal to the Width of the groove. 9. Pitch: It is the axial distance between a point on one thread and the corresponding Point on the next thread. It may be indicated as the distance from crest or from root of two adjacent threads. 10. Lead: It is the distance measured parallel to the axis from a point on a thread to the corresponding point on the same thread for one complete revolution. In other words, it is axial distance a screw advances in one revolution. 11. External thread: It is the thread on the outside surface of a member such as bolt, studs or screw. 12. Internal thread: It is the thread on the inside surface of a member such as nut or threaded hole. 13. Right hand thread: Right hand thread if turned clockwise direction advances into a threaded hole. It abbreviated as RH. 14. Left hand thread: Left hand thread if turned anticlockwise direction advances into a threaded hole. It abbreviated as LH.
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V- THREADS British standard whit worth thread (BSW) This thread was introduced by Sir Joseph whit worth, and was standardized as British standard thread. It has a thread angle of 55 degree and is rounded equally at crest and roots. British Association threads (B.A Threads) The angle between flanks is 47.5 degree. These threads are to supplement BSW and have fine pitches. They are used on screws for precision work. American standard threads (or) sellers thread The thread angle is 60 degree and both the crests and roots are kept flat. The sellers thread has been in use in USA and Canada. Unified screw threads The countries UK, U.S.A and Canada came to an arrangement for a common screw thread system with the included angle of 60 degree and designated as unified screw thread in the year 1949. The thread on the bolt is rounded off at the crest and root and the thread in the nut is rounded off at the root but the crest is left flat. This thread is very important in the motor and aeroplane industries and in chemical engineering. Unified thread can be either coarse (UNC) or fine (UNF) and unified national extra fine (UEF). ISO Metric Thread This is Indian standard thread for ISO (International Standard Organization). The included angle is 60 0 and the crests are flat and roots are round. Metric threads are grouped into diameter pitch combination differentiated by the pitch applied to specific diameters. There are coarse, constant, fine pitch series available. ISO metric threads are defined by nominal size (Basic major diameter) and pitch both expressed in millimeters. for example, a 10mm diameter, 1.25 pitches is expressed as M10?1.25. SQUARE THREADS Basic square thread The sides of these threads are normal to the axis and parallel to each other. The depth and the thickness of the thread are equal to half pitch. A square thread is designated by the letter SQ followed by nominal diameter pitch. For example a square thread of nominal diameter 30mm and pitch 6mm is designated as SQ 30?6. Acme Thread It is a modified form of square thread. It is easier to cut and is much stronger than square thread. It has a 29 0
thread angle. This inclined sides of the thread facilitate quick and early engagement and disengagement. It is used for power screws like lead screw of lathe, jackscrews, bench vices and valve operating screws.
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Buttress Thread The profile of this thread is a combination of square and V- threads. It combines the low frictional of square and ability to transmit power of square thread and the strength of V ? thread. It is used to transmit load in uni-direction. These threads are used in screw press, vices.
Knuckle Thread It is also a modification of square thread. The sharp corners of square thread are rounded off. This thread is used where heavy wear rough use is expected. The thread can be rolled or cast easily. It is used in railway carriage coupling screws, light bulbs and sockets, bottle caps etc and also objects made of brittle materials as glass, plastic, porcelains etc.
Types of thread profiles
Keys Keys are machine elements used to prevent relative rotational movement between a shaft and the parts mounted on it, such as pulleys, gears, wheels, couplings, etc. for making the joint, keyways are cut on the surface of the shaft and in the hub of the part to be mounted. After positioning the part on the shaft such that, both the keyways are properly aligned, the key is driven from the end, resulting in a firm joint. For mounting a part at any intermediate location on the shaft, first the key is firmly placed in the keyways of the shaft and then the part to be mounted is slid from one end of the shaft, till it is fully engaged with the key. Keys are classified into three types. 1. Saddle keys I. flat saddle key II. hollow saddle key
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2. Sunk keys I. taper sunk keys II. parallel sunk keys III. woodruff keys 3. Round keys
Types of keys
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Bolt and nuts A bolt and nut in combination is a fastening device used to hold two parts together. The body of the bolt, called shank is cylindrical in form, the head; square or hexagonal in shape, is formed by forging. Screw threads are cut on the other end of the shank. Nuts in general are square or hexagonal in shape. The nuts with internal threads engage with the corresponding size of the external threads of the bolt. However, there are other forms of nuts used to suit specific requirements. For nuts, hexagonal shape is preferred to the square one, as it is easy to tighten even in a limited space. This is because, with only one-sixth of a turn, the spanner can be reintroduced in the same position. However, square nuts are used when frequent loosening and tightening is required. The sharp corners on the head of bolts and nuts are removed by chamfering. Empirical portions of hexagonal and square head bolt & nut detail proportion Nominal diameter d = size of bolt or nut, mm Width across flats s = 1.5d+3 mm Width across corners e = 2d Thickness of bolt head k = 0.8d Thickness of nut, n = 0.9d Root diameter, d1 = d - (2 ? depth of thread) Length of the bolt L = as specified Thread length b = 2d+6mm (for l<150mm) = 2d+12mm (for l>150mm) Chamfer of bolt end, Z = (depth of thread ? 45 0 ) or =0.1d Chamfer angle of bolt head & nut 30 0
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1.5 Limits, fits and tolerances Limit System Following are some of the terms used in the limit system: Tolerance: The permissible variation of a size is called tolerance. It is the difference between the maximum and minimum permissible limits of the given size. If the variation is provided on one side of the basic size, it is termed as unilateral tolerance. Similarly, if the variation is provided on both sides of the basic size, it is known as bilateral tolerance. Limits: The two extreme permissible sizes between which the actual size is contained are called limits. The maximum size is called the upper limit and the minimum size is called the lower limit. Deviation: It is the algebraic difference between a size (actual, maximum, etc.) and the corresponding basic size. Actual deviation: It is the algebraic difference between the actual size and the corresponding basic size. Upper deviation: It is the algebraic difference between the maximum limit of the size and the corresponding basic size. Lower deviation: It is the algebraic difference between the minimum limit of the size and the corresponding basic size. Allowance: It is the dimensional difference between the maximum material limits of the mating parts, intentionally provided to obtain the desired class of fit. If the allowance is positive, it will result in minimum clearance between the mating parts and if the allowance is negative, it will result in maximum interference. Basic Size: It is determined solely from design calculations. If the strength and stiffness requirements need a 50mm diameter shaft, then 50mm is the basic shaft size. If it has to fit into a hole, then 50 mm is the basic size of the hole. Here, the two limit dimensions of the shaft are deviating in the negative direction with respect to the basic size and those of the hole in the positive direction. The line corresponding to the basic size is called the zero line or line of zero deviation.
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Fits The relation between two mating parts is known as a fit. Depending upon the actual limits of the hole or shaft sizes, fits may be classified as clearance fit, transition fit and interference fit.
Clearance Fit: It is a fit that gives a clearance between the two mating parts. minimum clearance: It is the difference between the minimum size of the hole and the maximum size of the shaft in a clearance fit. maximum clearance: It is the difference between the maximum size of the hole and the minimum size of the shaft in a clearance or transition fit. The fit between the shaft and hole in Fig. is a clearance fit that permits a minimum clearance (allowance) value of 29.95 ? 29.90 = + 0.05 mm and a maximum clearance of + 0.15 mm.
Transition Fit: This fit may result in either interference or a clearance, depending upon the actual values of the tolerance of individual parts. The shaft in Fig. may be either smaller or larger than the hole and still be within the prescribed tolerances. It results in a clearance fit, when shaft diameter is 29.95 and hole diameter is 30.05 (+ 0.10 mm) and interference fit, when shaft diameter is 30.00 and hole diameter 29.95 (? 0.05 mm).
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Interference fit: If the difference between the hole and shaft sizes is negative before assembly; an interference fit is obtained. minimum interference: It is the magnitude of the difference (negative) between the maximum size of the hole and the minimum size of the shaft in an interference fit before assembly. maximum interference: It is the magnitude of the difference between the minimum size of the hole and the maximum size of the shaft in an interference or a transition fit before assembly. The shaft in fig. is larger than the hole, so it requires a press fit, which has an effect similar to welding of two parts. The value of minimum interference is 30.25 ? 30.30 = ? 0.05 mm and maximum interference is 30.15 ? 30.40 = ? 0.25 mm.
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Schematic representation of fits:
Tolerance It is impossible to make anything to an exact size, therefore it is essential to allow a definite tolerance or permissible variation on every specified dimension. Tolerances are specified because ? Variations in properties of the material being machined introduce errors. ? The production machines themselves may have some inherent inaccuracies. ? It is impossible for an operator to make perfect settings. While setting up the tools and workpiece on the machine, some errors are likely to creep in.
Form variation: It is a variation of the actual condition of a form feature (surface, line) from geometrically ideal form. Position variation: It is a variation of the actual position of the form feature from the geometrically ideal position, with reference to another form (datum) feature. Geometrical tolerance: Geometrical tolerance is defined as the maximum permissible overall variation of form or position of a feature.
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Geometrical tolerances are used, (i) to specify the required accuracy in controlling the form of a feature, (ii) to ensure correct functional positioning of the feature, (iii) to ensure the interchangeability of components, and (iv) to facilitate the assembly of mating components. Tolerance zone: It is an imaginary area or volume within which the controlled feature of the manufactured component must be completely contained Datum: It is a theoretically exact geometric reference (such as axes, planes, straight lines, etc.) to which the tolerance features are related. Datum feature: A datum feature is a feature of a part, such as an edge, surface, or a hole, which forms the basis for a datum or is used to establish its location
Datum triangle: The datums are indicated by a leader line, terminating in a filled or an open triangle. Datum letter: To identify a datum for reference purposes, a capital letter is enclosed in a frame, connected to the datum triangle.
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Expt. No.02 INTRODUCTION TO CADD CADD is an electronic tool that enables us to make quick and accurate drawings. CADD has number of advantages over drawings created on a drawing board. Electronic drawings can be modified quite easily and can be represented in a variety of formats. CADD extends its power to yet another branch of engineering called computer aided manufacturing (CAM).CADD and manufacturing program are often integrated into one system called CAD-CAM. This system import CADD drawings into CAM program to automate the manufacturing process. When the design is finalized, the drawings are brought into a CAD-CAM system that uses numerical data from the CADD drawing for actual manufacturing. There is separate category of programs called Computer Aided Engineering (CAE) that can use CADD drawing for engineering analysis. The CAE programs have a number of applications in Structural Design, Civil Engineering, Mechanical Engineering and Electrical Engineering. The Mechanical engineer can test a machine assembly and also a prototype electronic model and test it without building a physical model. We can do amazing things with CADD that we never thought possible while creating drawings with pen or pencil. The following are some of the important capabilities that make CADD a powerful tool. ? Presentations ? Flexibility in editing ? Unit and accuracy levels ? Storage and access for drawings ? Sharing CADD drawings Presentations There are a number of ready-made presentations symbols available in CADD that can be used to enhance the look of drawings. In addition to prepare impressive presentations on paper, we can use CADD to make an on-screen presentations. Advanced CADD programs ever allow us to create an animated image. Flexibility in editing CADD allows us to work with great accuracy. If we need to create highly accuracy geometric shapes, CADD is the answer. It can help avoid time-consuming mathematical calculations. Unit and accuracy level We can work with as high precession as 1/1000 th of an inch. Storage and access of drawing A computer electronic filing system has the following advantages over the traditional filing system.
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? It is quick and convenient to organize CADD drawing in a computer. ? It enables us to create a highly organized environment. ? An electronic drawing never gets old and faded. Sharing CADD Drawing The electronic drawing can be shared by a number of users, allowing them to Co-ordinate projects and work as a team. This is accomplished by connecting different computer via a network.
About AutoCAD
AutoCAD is a Computer Aided Design (CAD) program used by just about every Engineering and Design office in the world. Although there are alternative CAD packages, AutoCAD is by far the most widely used system. Autodesk's AutoCAD is the industry leader in CAD packages. Used by Civil Engineers, Architects, Mechanical and Electrical Engineers, Aeronautical Engineers plus many other disciplines. There have been several versions of AutoCAD over the years, with each new version introducing new and more powerful features than its predecessor. The latest version of AutoCAD (at the time of writing) is AutoCAD 2011. Any courses, whether through community colleges or online universities, that are related to Engineering or Architecture should be considered incomplete if they do not introduce students to AutoCAD. Accurate, scale drawings can be created and published using AutoCAD powerful features. 3D 'models' can also be created giving the designer absolute control over the design from start to finish. The computerized model can be viewed through a 360? angle, and even 'rendered' with a texture on screen to give an idea of the finished product. Co-ordinate system
AutoCAD uses points to determine where an object is located. There is an origin where it begins counting from. This point is (0,0). Every object is located in relation to the origin. If we were to draw a line straight out to the right from FirstRanker.com - FirstRanker's Choice
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DEPARTMENT OF MECHANICAL ENGINEERING
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
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College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
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PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
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To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
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ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
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Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
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Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
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The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
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The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
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1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
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Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power
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Terms and Nomenclature
1. Crest: It is the peak edge of a screw thread that connects the adjacent flanks at the top. 2. Root: It is the bottom edge of the thread that connects the adjacent flanks at the bottom. 3. Flank or side: It is the straight portion of the surface, on either side of the screw thread. 4. Angle of the thread: It is the angle included between the sides of two adjacent threads measured on an axial plane. 5. Depth of the thread: It is the distance between the crest and the root measured at Right angle to the axis. It is equal to half the difference between the outer diameter and the core diameter. 6. Major diameter or outside diameter: It is the diameter of the imaginary coaxial cylinder, which would bind the crests of an external or internal thread. 7. Minor or core or root diameter: It is the diameter of the imaginary coaxial cylinder; this would bind the roots of an external thread or of an internal thread. 8. Pitch diameter: It is the diameter of the imaginary coaxial cylinder that can be passed so as to cut the thread, that the width of the cut thread will be equal to the Width of the groove. 9. Pitch: It is the axial distance between a point on one thread and the corresponding Point on the next thread. It may be indicated as the distance from crest or from root of two adjacent threads. 10. Lead: It is the distance measured parallel to the axis from a point on a thread to the corresponding point on the same thread for one complete revolution. In other words, it is axial distance a screw advances in one revolution. 11. External thread: It is the thread on the outside surface of a member such as bolt, studs or screw. 12. Internal thread: It is the thread on the inside surface of a member such as nut or threaded hole. 13. Right hand thread: Right hand thread if turned clockwise direction advances into a threaded hole. It abbreviated as RH. 14. Left hand thread: Left hand thread if turned anticlockwise direction advances into a threaded hole. It abbreviated as LH.
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V- THREADS British standard whit worth thread (BSW) This thread was introduced by Sir Joseph whit worth, and was standardized as British standard thread. It has a thread angle of 55 degree and is rounded equally at crest and roots. British Association threads (B.A Threads) The angle between flanks is 47.5 degree. These threads are to supplement BSW and have fine pitches. They are used on screws for precision work. American standard threads (or) sellers thread The thread angle is 60 degree and both the crests and roots are kept flat. The sellers thread has been in use in USA and Canada. Unified screw threads The countries UK, U.S.A and Canada came to an arrangement for a common screw thread system with the included angle of 60 degree and designated as unified screw thread in the year 1949. The thread on the bolt is rounded off at the crest and root and the thread in the nut is rounded off at the root but the crest is left flat. This thread is very important in the motor and aeroplane industries and in chemical engineering. Unified thread can be either coarse (UNC) or fine (UNF) and unified national extra fine (UEF). ISO Metric Thread This is Indian standard thread for ISO (International Standard Organization). The included angle is 60 0 and the crests are flat and roots are round. Metric threads are grouped into diameter pitch combination differentiated by the pitch applied to specific diameters. There are coarse, constant, fine pitch series available. ISO metric threads are defined by nominal size (Basic major diameter) and pitch both expressed in millimeters. for example, a 10mm diameter, 1.25 pitches is expressed as M10?1.25. SQUARE THREADS Basic square thread The sides of these threads are normal to the axis and parallel to each other. The depth and the thickness of the thread are equal to half pitch. A square thread is designated by the letter SQ followed by nominal diameter pitch. For example a square thread of nominal diameter 30mm and pitch 6mm is designated as SQ 30?6. Acme Thread It is a modified form of square thread. It is easier to cut and is much stronger than square thread. It has a 29 0
thread angle. This inclined sides of the thread facilitate quick and early engagement and disengagement. It is used for power screws like lead screw of lathe, jackscrews, bench vices and valve operating screws.
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Buttress Thread The profile of this thread is a combination of square and V- threads. It combines the low frictional of square and ability to transmit power of square thread and the strength of V ? thread. It is used to transmit load in uni-direction. These threads are used in screw press, vices.
Knuckle Thread It is also a modification of square thread. The sharp corners of square thread are rounded off. This thread is used where heavy wear rough use is expected. The thread can be rolled or cast easily. It is used in railway carriage coupling screws, light bulbs and sockets, bottle caps etc and also objects made of brittle materials as glass, plastic, porcelains etc.
Types of thread profiles
Keys Keys are machine elements used to prevent relative rotational movement between a shaft and the parts mounted on it, such as pulleys, gears, wheels, couplings, etc. for making the joint, keyways are cut on the surface of the shaft and in the hub of the part to be mounted. After positioning the part on the shaft such that, both the keyways are properly aligned, the key is driven from the end, resulting in a firm joint. For mounting a part at any intermediate location on the shaft, first the key is firmly placed in the keyways of the shaft and then the part to be mounted is slid from one end of the shaft, till it is fully engaged with the key. Keys are classified into three types. 1. Saddle keys I. flat saddle key II. hollow saddle key
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2. Sunk keys I. taper sunk keys II. parallel sunk keys III. woodruff keys 3. Round keys
Types of keys
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Bolt and nuts A bolt and nut in combination is a fastening device used to hold two parts together. The body of the bolt, called shank is cylindrical in form, the head; square or hexagonal in shape, is formed by forging. Screw threads are cut on the other end of the shank. Nuts in general are square or hexagonal in shape. The nuts with internal threads engage with the corresponding size of the external threads of the bolt. However, there are other forms of nuts used to suit specific requirements. For nuts, hexagonal shape is preferred to the square one, as it is easy to tighten even in a limited space. This is because, with only one-sixth of a turn, the spanner can be reintroduced in the same position. However, square nuts are used when frequent loosening and tightening is required. The sharp corners on the head of bolts and nuts are removed by chamfering. Empirical portions of hexagonal and square head bolt & nut detail proportion Nominal diameter d = size of bolt or nut, mm Width across flats s = 1.5d+3 mm Width across corners e = 2d Thickness of bolt head k = 0.8d Thickness of nut, n = 0.9d Root diameter, d1 = d - (2 ? depth of thread) Length of the bolt L = as specified Thread length b = 2d+6mm (for l<150mm) = 2d+12mm (for l>150mm) Chamfer of bolt end, Z = (depth of thread ? 45 0 ) or =0.1d Chamfer angle of bolt head & nut 30 0
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1.5 Limits, fits and tolerances Limit System Following are some of the terms used in the limit system: Tolerance: The permissible variation of a size is called tolerance. It is the difference between the maximum and minimum permissible limits of the given size. If the variation is provided on one side of the basic size, it is termed as unilateral tolerance. Similarly, if the variation is provided on both sides of the basic size, it is known as bilateral tolerance. Limits: The two extreme permissible sizes between which the actual size is contained are called limits. The maximum size is called the upper limit and the minimum size is called the lower limit. Deviation: It is the algebraic difference between a size (actual, maximum, etc.) and the corresponding basic size. Actual deviation: It is the algebraic difference between the actual size and the corresponding basic size. Upper deviation: It is the algebraic difference between the maximum limit of the size and the corresponding basic size. Lower deviation: It is the algebraic difference between the minimum limit of the size and the corresponding basic size. Allowance: It is the dimensional difference between the maximum material limits of the mating parts, intentionally provided to obtain the desired class of fit. If the allowance is positive, it will result in minimum clearance between the mating parts and if the allowance is negative, it will result in maximum interference. Basic Size: It is determined solely from design calculations. If the strength and stiffness requirements need a 50mm diameter shaft, then 50mm is the basic shaft size. If it has to fit into a hole, then 50 mm is the basic size of the hole. Here, the two limit dimensions of the shaft are deviating in the negative direction with respect to the basic size and those of the hole in the positive direction. The line corresponding to the basic size is called the zero line or line of zero deviation.
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Fits The relation between two mating parts is known as a fit. Depending upon the actual limits of the hole or shaft sizes, fits may be classified as clearance fit, transition fit and interference fit.
Clearance Fit: It is a fit that gives a clearance between the two mating parts. minimum clearance: It is the difference between the minimum size of the hole and the maximum size of the shaft in a clearance fit. maximum clearance: It is the difference between the maximum size of the hole and the minimum size of the shaft in a clearance or transition fit. The fit between the shaft and hole in Fig. is a clearance fit that permits a minimum clearance (allowance) value of 29.95 ? 29.90 = + 0.05 mm and a maximum clearance of + 0.15 mm.
Transition Fit: This fit may result in either interference or a clearance, depending upon the actual values of the tolerance of individual parts. The shaft in Fig. may be either smaller or larger than the hole and still be within the prescribed tolerances. It results in a clearance fit, when shaft diameter is 29.95 and hole diameter is 30.05 (+ 0.10 mm) and interference fit, when shaft diameter is 30.00 and hole diameter 29.95 (? 0.05 mm).
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Interference fit: If the difference between the hole and shaft sizes is negative before assembly; an interference fit is obtained. minimum interference: It is the magnitude of the difference (negative) between the maximum size of the hole and the minimum size of the shaft in an interference fit before assembly. maximum interference: It is the magnitude of the difference between the minimum size of the hole and the maximum size of the shaft in an interference or a transition fit before assembly. The shaft in fig. is larger than the hole, so it requires a press fit, which has an effect similar to welding of two parts. The value of minimum interference is 30.25 ? 30.30 = ? 0.05 mm and maximum interference is 30.15 ? 30.40 = ? 0.25 mm.
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Schematic representation of fits:
Tolerance It is impossible to make anything to an exact size, therefore it is essential to allow a definite tolerance or permissible variation on every specified dimension. Tolerances are specified because ? Variations in properties of the material being machined introduce errors. ? The production machines themselves may have some inherent inaccuracies. ? It is impossible for an operator to make perfect settings. While setting up the tools and workpiece on the machine, some errors are likely to creep in.
Form variation: It is a variation of the actual condition of a form feature (surface, line) from geometrically ideal form. Position variation: It is a variation of the actual position of the form feature from the geometrically ideal position, with reference to another form (datum) feature. Geometrical tolerance: Geometrical tolerance is defined as the maximum permissible overall variation of form or position of a feature.
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Geometrical tolerances are used, (i) to specify the required accuracy in controlling the form of a feature, (ii) to ensure correct functional positioning of the feature, (iii) to ensure the interchangeability of components, and (iv) to facilitate the assembly of mating components. Tolerance zone: It is an imaginary area or volume within which the controlled feature of the manufactured component must be completely contained Datum: It is a theoretically exact geometric reference (such as axes, planes, straight lines, etc.) to which the tolerance features are related. Datum feature: A datum feature is a feature of a part, such as an edge, surface, or a hole, which forms the basis for a datum or is used to establish its location
Datum triangle: The datums are indicated by a leader line, terminating in a filled or an open triangle. Datum letter: To identify a datum for reference purposes, a capital letter is enclosed in a frame, connected to the datum triangle.
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Expt. No.02 INTRODUCTION TO CADD CADD is an electronic tool that enables us to make quick and accurate drawings. CADD has number of advantages over drawings created on a drawing board. Electronic drawings can be modified quite easily and can be represented in a variety of formats. CADD extends its power to yet another branch of engineering called computer aided manufacturing (CAM).CADD and manufacturing program are often integrated into one system called CAD-CAM. This system import CADD drawings into CAM program to automate the manufacturing process. When the design is finalized, the drawings are brought into a CAD-CAM system that uses numerical data from the CADD drawing for actual manufacturing. There is separate category of programs called Computer Aided Engineering (CAE) that can use CADD drawing for engineering analysis. The CAE programs have a number of applications in Structural Design, Civil Engineering, Mechanical Engineering and Electrical Engineering. The Mechanical engineer can test a machine assembly and also a prototype electronic model and test it without building a physical model. We can do amazing things with CADD that we never thought possible while creating drawings with pen or pencil. The following are some of the important capabilities that make CADD a powerful tool. ? Presentations ? Flexibility in editing ? Unit and accuracy levels ? Storage and access for drawings ? Sharing CADD drawings Presentations There are a number of ready-made presentations symbols available in CADD that can be used to enhance the look of drawings. In addition to prepare impressive presentations on paper, we can use CADD to make an on-screen presentations. Advanced CADD programs ever allow us to create an animated image. Flexibility in editing CADD allows us to work with great accuracy. If we need to create highly accuracy geometric shapes, CADD is the answer. It can help avoid time-consuming mathematical calculations. Unit and accuracy level We can work with as high precession as 1/1000 th of an inch. Storage and access of drawing A computer electronic filing system has the following advantages over the traditional filing system.
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? It is quick and convenient to organize CADD drawing in a computer. ? It enables us to create a highly organized environment. ? An electronic drawing never gets old and faded. Sharing CADD Drawing The electronic drawing can be shared by a number of users, allowing them to Co-ordinate projects and work as a team. This is accomplished by connecting different computer via a network.
About AutoCAD
AutoCAD is a Computer Aided Design (CAD) program used by just about every Engineering and Design office in the world. Although there are alternative CAD packages, AutoCAD is by far the most widely used system. Autodesk's AutoCAD is the industry leader in CAD packages. Used by Civil Engineers, Architects, Mechanical and Electrical Engineers, Aeronautical Engineers plus many other disciplines. There have been several versions of AutoCAD over the years, with each new version introducing new and more powerful features than its predecessor. The latest version of AutoCAD (at the time of writing) is AutoCAD 2011. Any courses, whether through community colleges or online universities, that are related to Engineering or Architecture should be considered incomplete if they do not introduce students to AutoCAD. Accurate, scale drawings can be created and published using AutoCAD powerful features. 3D 'models' can also be created giving the designer absolute control over the design from start to finish. The computerized model can be viewed through a 360? angle, and even 'rendered' with a texture on screen to give an idea of the finished product. Co-ordinate system
AutoCAD uses points to determine where an object is located. There is an origin where it begins counting from. This point is (0,0). Every object is located in relation to the origin. If we were to draw a line straight out to the right from
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the origin, this would be considered the positive X-axis. If we were to draw a line straight up, this would be the positive Y-axis. The picture above shows a point located at (9, 6). This means that the point is 9 units over in the X- axis and 6 units up in the Y-axis. When we are working with points, X always comes first. The other point shown is (-10,-4). This means that the point is 10 units in the negative X-axis (left) and 4 units in the negative Y-axis (down).
A line has two points, a start point and an end point. AutoCAD works with the points to display the line on the screen. Most of the time we will not have an indication of where the origin is. We may need to draw a line from the endpoint of an existing line. To do this we use relative points. These work the same way, but we have to add the @ symbol (shift+2) to tell AutoCAD that this next point is relative from the last point entered. i.e. 1. ABSOLUTE POINTS are exact points on the drawing space. 2. RELATIVE POINTS are relative to an OBJECT on the drawing space Angular Measurement AutoCAD measures angles in a particular way also.
When drawing lines at an angle, we have to begin measuring the angle from 0 degrees, which is at the 3 o'clock position. If we drew a line at 90 degrees, it would go straight up. The example shows a line drawn at +300 degrees (270+30), or -60 degrees.
Entering Points in AutoCAD We can enter points directly on the command line using three different systems. The one we use will depend on which is more applicable for the situation. The three systems are as follows:
ABSOLUTE CO-ORDINATES - Using this method, we enter the points as they relate to the origin of the WCS. To enter a point just enters in the exact point as X, Y. FirstRanker.com - FirstRanker's Choice
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DEPARTMENT OF MECHANICAL ENGINEERING
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
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College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
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PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
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To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
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ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
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Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
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Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
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The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
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The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
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1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
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Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power
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Terms and Nomenclature
1. Crest: It is the peak edge of a screw thread that connects the adjacent flanks at the top. 2. Root: It is the bottom edge of the thread that connects the adjacent flanks at the bottom. 3. Flank or side: It is the straight portion of the surface, on either side of the screw thread. 4. Angle of the thread: It is the angle included between the sides of two adjacent threads measured on an axial plane. 5. Depth of the thread: It is the distance between the crest and the root measured at Right angle to the axis. It is equal to half the difference between the outer diameter and the core diameter. 6. Major diameter or outside diameter: It is the diameter of the imaginary coaxial cylinder, which would bind the crests of an external or internal thread. 7. Minor or core or root diameter: It is the diameter of the imaginary coaxial cylinder; this would bind the roots of an external thread or of an internal thread. 8. Pitch diameter: It is the diameter of the imaginary coaxial cylinder that can be passed so as to cut the thread, that the width of the cut thread will be equal to the Width of the groove. 9. Pitch: It is the axial distance between a point on one thread and the corresponding Point on the next thread. It may be indicated as the distance from crest or from root of two adjacent threads. 10. Lead: It is the distance measured parallel to the axis from a point on a thread to the corresponding point on the same thread for one complete revolution. In other words, it is axial distance a screw advances in one revolution. 11. External thread: It is the thread on the outside surface of a member such as bolt, studs or screw. 12. Internal thread: It is the thread on the inside surface of a member such as nut or threaded hole. 13. Right hand thread: Right hand thread if turned clockwise direction advances into a threaded hole. It abbreviated as RH. 14. Left hand thread: Left hand thread if turned anticlockwise direction advances into a threaded hole. It abbreviated as LH.
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V- THREADS British standard whit worth thread (BSW) This thread was introduced by Sir Joseph whit worth, and was standardized as British standard thread. It has a thread angle of 55 degree and is rounded equally at crest and roots. British Association threads (B.A Threads) The angle between flanks is 47.5 degree. These threads are to supplement BSW and have fine pitches. They are used on screws for precision work. American standard threads (or) sellers thread The thread angle is 60 degree and both the crests and roots are kept flat. The sellers thread has been in use in USA and Canada. Unified screw threads The countries UK, U.S.A and Canada came to an arrangement for a common screw thread system with the included angle of 60 degree and designated as unified screw thread in the year 1949. The thread on the bolt is rounded off at the crest and root and the thread in the nut is rounded off at the root but the crest is left flat. This thread is very important in the motor and aeroplane industries and in chemical engineering. Unified thread can be either coarse (UNC) or fine (UNF) and unified national extra fine (UEF). ISO Metric Thread This is Indian standard thread for ISO (International Standard Organization). The included angle is 60 0 and the crests are flat and roots are round. Metric threads are grouped into diameter pitch combination differentiated by the pitch applied to specific diameters. There are coarse, constant, fine pitch series available. ISO metric threads are defined by nominal size (Basic major diameter) and pitch both expressed in millimeters. for example, a 10mm diameter, 1.25 pitches is expressed as M10?1.25. SQUARE THREADS Basic square thread The sides of these threads are normal to the axis and parallel to each other. The depth and the thickness of the thread are equal to half pitch. A square thread is designated by the letter SQ followed by nominal diameter pitch. For example a square thread of nominal diameter 30mm and pitch 6mm is designated as SQ 30?6. Acme Thread It is a modified form of square thread. It is easier to cut and is much stronger than square thread. It has a 29 0
thread angle. This inclined sides of the thread facilitate quick and early engagement and disengagement. It is used for power screws like lead screw of lathe, jackscrews, bench vices and valve operating screws.
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Buttress Thread The profile of this thread is a combination of square and V- threads. It combines the low frictional of square and ability to transmit power of square thread and the strength of V ? thread. It is used to transmit load in uni-direction. These threads are used in screw press, vices.
Knuckle Thread It is also a modification of square thread. The sharp corners of square thread are rounded off. This thread is used where heavy wear rough use is expected. The thread can be rolled or cast easily. It is used in railway carriage coupling screws, light bulbs and sockets, bottle caps etc and also objects made of brittle materials as glass, plastic, porcelains etc.
Types of thread profiles
Keys Keys are machine elements used to prevent relative rotational movement between a shaft and the parts mounted on it, such as pulleys, gears, wheels, couplings, etc. for making the joint, keyways are cut on the surface of the shaft and in the hub of the part to be mounted. After positioning the part on the shaft such that, both the keyways are properly aligned, the key is driven from the end, resulting in a firm joint. For mounting a part at any intermediate location on the shaft, first the key is firmly placed in the keyways of the shaft and then the part to be mounted is slid from one end of the shaft, till it is fully engaged with the key. Keys are classified into three types. 1. Saddle keys I. flat saddle key II. hollow saddle key
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2. Sunk keys I. taper sunk keys II. parallel sunk keys III. woodruff keys 3. Round keys
Types of keys
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Bolt and nuts A bolt and nut in combination is a fastening device used to hold two parts together. The body of the bolt, called shank is cylindrical in form, the head; square or hexagonal in shape, is formed by forging. Screw threads are cut on the other end of the shank. Nuts in general are square or hexagonal in shape. The nuts with internal threads engage with the corresponding size of the external threads of the bolt. However, there are other forms of nuts used to suit specific requirements. For nuts, hexagonal shape is preferred to the square one, as it is easy to tighten even in a limited space. This is because, with only one-sixth of a turn, the spanner can be reintroduced in the same position. However, square nuts are used when frequent loosening and tightening is required. The sharp corners on the head of bolts and nuts are removed by chamfering. Empirical portions of hexagonal and square head bolt & nut detail proportion Nominal diameter d = size of bolt or nut, mm Width across flats s = 1.5d+3 mm Width across corners e = 2d Thickness of bolt head k = 0.8d Thickness of nut, n = 0.9d Root diameter, d1 = d - (2 ? depth of thread) Length of the bolt L = as specified Thread length b = 2d+6mm (for l<150mm) = 2d+12mm (for l>150mm) Chamfer of bolt end, Z = (depth of thread ? 45 0 ) or =0.1d Chamfer angle of bolt head & nut 30 0
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1.5 Limits, fits and tolerances Limit System Following are some of the terms used in the limit system: Tolerance: The permissible variation of a size is called tolerance. It is the difference between the maximum and minimum permissible limits of the given size. If the variation is provided on one side of the basic size, it is termed as unilateral tolerance. Similarly, if the variation is provided on both sides of the basic size, it is known as bilateral tolerance. Limits: The two extreme permissible sizes between which the actual size is contained are called limits. The maximum size is called the upper limit and the minimum size is called the lower limit. Deviation: It is the algebraic difference between a size (actual, maximum, etc.) and the corresponding basic size. Actual deviation: It is the algebraic difference between the actual size and the corresponding basic size. Upper deviation: It is the algebraic difference between the maximum limit of the size and the corresponding basic size. Lower deviation: It is the algebraic difference between the minimum limit of the size and the corresponding basic size. Allowance: It is the dimensional difference between the maximum material limits of the mating parts, intentionally provided to obtain the desired class of fit. If the allowance is positive, it will result in minimum clearance between the mating parts and if the allowance is negative, it will result in maximum interference. Basic Size: It is determined solely from design calculations. If the strength and stiffness requirements need a 50mm diameter shaft, then 50mm is the basic shaft size. If it has to fit into a hole, then 50 mm is the basic size of the hole. Here, the two limit dimensions of the shaft are deviating in the negative direction with respect to the basic size and those of the hole in the positive direction. The line corresponding to the basic size is called the zero line or line of zero deviation.
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Fits The relation between two mating parts is known as a fit. Depending upon the actual limits of the hole or shaft sizes, fits may be classified as clearance fit, transition fit and interference fit.
Clearance Fit: It is a fit that gives a clearance between the two mating parts. minimum clearance: It is the difference between the minimum size of the hole and the maximum size of the shaft in a clearance fit. maximum clearance: It is the difference between the maximum size of the hole and the minimum size of the shaft in a clearance or transition fit. The fit between the shaft and hole in Fig. is a clearance fit that permits a minimum clearance (allowance) value of 29.95 ? 29.90 = + 0.05 mm and a maximum clearance of + 0.15 mm.
Transition Fit: This fit may result in either interference or a clearance, depending upon the actual values of the tolerance of individual parts. The shaft in Fig. may be either smaller or larger than the hole and still be within the prescribed tolerances. It results in a clearance fit, when shaft diameter is 29.95 and hole diameter is 30.05 (+ 0.10 mm) and interference fit, when shaft diameter is 30.00 and hole diameter 29.95 (? 0.05 mm).
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Interference fit: If the difference between the hole and shaft sizes is negative before assembly; an interference fit is obtained. minimum interference: It is the magnitude of the difference (negative) between the maximum size of the hole and the minimum size of the shaft in an interference fit before assembly. maximum interference: It is the magnitude of the difference between the minimum size of the hole and the maximum size of the shaft in an interference or a transition fit before assembly. The shaft in fig. is larger than the hole, so it requires a press fit, which has an effect similar to welding of two parts. The value of minimum interference is 30.25 ? 30.30 = ? 0.05 mm and maximum interference is 30.15 ? 30.40 = ? 0.25 mm.
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Schematic representation of fits:
Tolerance It is impossible to make anything to an exact size, therefore it is essential to allow a definite tolerance or permissible variation on every specified dimension. Tolerances are specified because ? Variations in properties of the material being machined introduce errors. ? The production machines themselves may have some inherent inaccuracies. ? It is impossible for an operator to make perfect settings. While setting up the tools and workpiece on the machine, some errors are likely to creep in.
Form variation: It is a variation of the actual condition of a form feature (surface, line) from geometrically ideal form. Position variation: It is a variation of the actual position of the form feature from the geometrically ideal position, with reference to another form (datum) feature. Geometrical tolerance: Geometrical tolerance is defined as the maximum permissible overall variation of form or position of a feature.
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Geometrical tolerances are used, (i) to specify the required accuracy in controlling the form of a feature, (ii) to ensure correct functional positioning of the feature, (iii) to ensure the interchangeability of components, and (iv) to facilitate the assembly of mating components. Tolerance zone: It is an imaginary area or volume within which the controlled feature of the manufactured component must be completely contained Datum: It is a theoretically exact geometric reference (such as axes, planes, straight lines, etc.) to which the tolerance features are related. Datum feature: A datum feature is a feature of a part, such as an edge, surface, or a hole, which forms the basis for a datum or is used to establish its location
Datum triangle: The datums are indicated by a leader line, terminating in a filled or an open triangle. Datum letter: To identify a datum for reference purposes, a capital letter is enclosed in a frame, connected to the datum triangle.
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Expt. No.02 INTRODUCTION TO CADD CADD is an electronic tool that enables us to make quick and accurate drawings. CADD has number of advantages over drawings created on a drawing board. Electronic drawings can be modified quite easily and can be represented in a variety of formats. CADD extends its power to yet another branch of engineering called computer aided manufacturing (CAM).CADD and manufacturing program are often integrated into one system called CAD-CAM. This system import CADD drawings into CAM program to automate the manufacturing process. When the design is finalized, the drawings are brought into a CAD-CAM system that uses numerical data from the CADD drawing for actual manufacturing. There is separate category of programs called Computer Aided Engineering (CAE) that can use CADD drawing for engineering analysis. The CAE programs have a number of applications in Structural Design, Civil Engineering, Mechanical Engineering and Electrical Engineering. The Mechanical engineer can test a machine assembly and also a prototype electronic model and test it without building a physical model. We can do amazing things with CADD that we never thought possible while creating drawings with pen or pencil. The following are some of the important capabilities that make CADD a powerful tool. ? Presentations ? Flexibility in editing ? Unit and accuracy levels ? Storage and access for drawings ? Sharing CADD drawings Presentations There are a number of ready-made presentations symbols available in CADD that can be used to enhance the look of drawings. In addition to prepare impressive presentations on paper, we can use CADD to make an on-screen presentations. Advanced CADD programs ever allow us to create an animated image. Flexibility in editing CADD allows us to work with great accuracy. If we need to create highly accuracy geometric shapes, CADD is the answer. It can help avoid time-consuming mathematical calculations. Unit and accuracy level We can work with as high precession as 1/1000 th of an inch. Storage and access of drawing A computer electronic filing system has the following advantages over the traditional filing system.
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? It is quick and convenient to organize CADD drawing in a computer. ? It enables us to create a highly organized environment. ? An electronic drawing never gets old and faded. Sharing CADD Drawing The electronic drawing can be shared by a number of users, allowing them to Co-ordinate projects and work as a team. This is accomplished by connecting different computer via a network.
About AutoCAD
AutoCAD is a Computer Aided Design (CAD) program used by just about every Engineering and Design office in the world. Although there are alternative CAD packages, AutoCAD is by far the most widely used system. Autodesk's AutoCAD is the industry leader in CAD packages. Used by Civil Engineers, Architects, Mechanical and Electrical Engineers, Aeronautical Engineers plus many other disciplines. There have been several versions of AutoCAD over the years, with each new version introducing new and more powerful features than its predecessor. The latest version of AutoCAD (at the time of writing) is AutoCAD 2011. Any courses, whether through community colleges or online universities, that are related to Engineering or Architecture should be considered incomplete if they do not introduce students to AutoCAD. Accurate, scale drawings can be created and published using AutoCAD powerful features. 3D 'models' can also be created giving the designer absolute control over the design from start to finish. The computerized model can be viewed through a 360? angle, and even 'rendered' with a texture on screen to give an idea of the finished product. Co-ordinate system
AutoCAD uses points to determine where an object is located. There is an origin where it begins counting from. This point is (0,0). Every object is located in relation to the origin. If we were to draw a line straight out to the right from
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the origin, this would be considered the positive X-axis. If we were to draw a line straight up, this would be the positive Y-axis. The picture above shows a point located at (9, 6). This means that the point is 9 units over in the X- axis and 6 units up in the Y-axis. When we are working with points, X always comes first. The other point shown is (-10,-4). This means that the point is 10 units in the negative X-axis (left) and 4 units in the negative Y-axis (down).
A line has two points, a start point and an end point. AutoCAD works with the points to display the line on the screen. Most of the time we will not have an indication of where the origin is. We may need to draw a line from the endpoint of an existing line. To do this we use relative points. These work the same way, but we have to add the @ symbol (shift+2) to tell AutoCAD that this next point is relative from the last point entered. i.e. 1. ABSOLUTE POINTS are exact points on the drawing space. 2. RELATIVE POINTS are relative to an OBJECT on the drawing space Angular Measurement AutoCAD measures angles in a particular way also.
When drawing lines at an angle, we have to begin measuring the angle from 0 degrees, which is at the 3 o'clock position. If we drew a line at 90 degrees, it would go straight up. The example shows a line drawn at +300 degrees (270+30), or -60 degrees.
Entering Points in AutoCAD We can enter points directly on the command line using three different systems. The one we use will depend on which is more applicable for the situation. The three systems are as follows:
ABSOLUTE CO-ORDINATES - Using this method, we enter the points as they relate to the origin of the WCS. To enter a point just enters in the exact point as X, Y.
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RELATIVE CO-ORDINATES - This allows us to enter points in relation to the first point we have entered. After we've entered one point, the next would be entered as @X, Y. This means that AutoCAD will draw a line from the first point to another point X units over and Y units up relative to the previous point. POLAR CO-ORDINATES - We would use this system if we know that we want to draw a line a certain distance at a particular angle. We would enter this as @D@10<90 will draw a line 10 units straight up from the first point. The three ways of entering co-ordinates shown above are the ONLY way AutoCAD accepts input. First decide which style we need to use, and then enter as shown. Remember that X is always before Y (alphabetical). Don't forget the '@' symbol when we are entering relative points. AutoCAD Basics Application Button - This button displays commands for printing, saving, drawing utilities and other non-drawing tool. Quick Access Toolbar - This is for quick access to common commands like New, Open, Save, Plot Filename - The name of the current file we are working on. Search Bar - Search for text in were drawing or search the help files. Ribbon - The Ribbon has most of the commands/tools that we will use while we are working. Tabs - A series of Tabs make up the Ribbon (Home, Insert, Manage, etc) and organize the Tools into common groups. Panels - Contain a group of tools Tools - These are the icon that starts the commands we use to draw, modify, etc. Tool Tip - If we however mouse over a tool, a tool tip will appear to give us more information. Hold it longer for more info. Drawing Space - These is where we draw were designs. Command line - When we type a command, we will see it here. AutoCAD uses this space to 'prompt' us for information. It will give us a lot of information and tell us where we are in the command. Status bar - This allows seeing and changing different modes of drawing such as Ortho, Osnaps, Grid, Otrack, etc. We can right click this area to toggle between icons and text for this area.
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
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College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
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PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
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To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
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ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
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Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
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Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
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The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
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The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
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1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
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Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power
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Terms and Nomenclature
1. Crest: It is the peak edge of a screw thread that connects the adjacent flanks at the top. 2. Root: It is the bottom edge of the thread that connects the adjacent flanks at the bottom. 3. Flank or side: It is the straight portion of the surface, on either side of the screw thread. 4. Angle of the thread: It is the angle included between the sides of two adjacent threads measured on an axial plane. 5. Depth of the thread: It is the distance between the crest and the root measured at Right angle to the axis. It is equal to half the difference between the outer diameter and the core diameter. 6. Major diameter or outside diameter: It is the diameter of the imaginary coaxial cylinder, which would bind the crests of an external or internal thread. 7. Minor or core or root diameter: It is the diameter of the imaginary coaxial cylinder; this would bind the roots of an external thread or of an internal thread. 8. Pitch diameter: It is the diameter of the imaginary coaxial cylinder that can be passed so as to cut the thread, that the width of the cut thread will be equal to the Width of the groove. 9. Pitch: It is the axial distance between a point on one thread and the corresponding Point on the next thread. It may be indicated as the distance from crest or from root of two adjacent threads. 10. Lead: It is the distance measured parallel to the axis from a point on a thread to the corresponding point on the same thread for one complete revolution. In other words, it is axial distance a screw advances in one revolution. 11. External thread: It is the thread on the outside surface of a member such as bolt, studs or screw. 12. Internal thread: It is the thread on the inside surface of a member such as nut or threaded hole. 13. Right hand thread: Right hand thread if turned clockwise direction advances into a threaded hole. It abbreviated as RH. 14. Left hand thread: Left hand thread if turned anticlockwise direction advances into a threaded hole. It abbreviated as LH.
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V- THREADS British standard whit worth thread (BSW) This thread was introduced by Sir Joseph whit worth, and was standardized as British standard thread. It has a thread angle of 55 degree and is rounded equally at crest and roots. British Association threads (B.A Threads) The angle between flanks is 47.5 degree. These threads are to supplement BSW and have fine pitches. They are used on screws for precision work. American standard threads (or) sellers thread The thread angle is 60 degree and both the crests and roots are kept flat. The sellers thread has been in use in USA and Canada. Unified screw threads The countries UK, U.S.A and Canada came to an arrangement for a common screw thread system with the included angle of 60 degree and designated as unified screw thread in the year 1949. The thread on the bolt is rounded off at the crest and root and the thread in the nut is rounded off at the root but the crest is left flat. This thread is very important in the motor and aeroplane industries and in chemical engineering. Unified thread can be either coarse (UNC) or fine (UNF) and unified national extra fine (UEF). ISO Metric Thread This is Indian standard thread for ISO (International Standard Organization). The included angle is 60 0 and the crests are flat and roots are round. Metric threads are grouped into diameter pitch combination differentiated by the pitch applied to specific diameters. There are coarse, constant, fine pitch series available. ISO metric threads are defined by nominal size (Basic major diameter) and pitch both expressed in millimeters. for example, a 10mm diameter, 1.25 pitches is expressed as M10?1.25. SQUARE THREADS Basic square thread The sides of these threads are normal to the axis and parallel to each other. The depth and the thickness of the thread are equal to half pitch. A square thread is designated by the letter SQ followed by nominal diameter pitch. For example a square thread of nominal diameter 30mm and pitch 6mm is designated as SQ 30?6. Acme Thread It is a modified form of square thread. It is easier to cut and is much stronger than square thread. It has a 29 0
thread angle. This inclined sides of the thread facilitate quick and early engagement and disengagement. It is used for power screws like lead screw of lathe, jackscrews, bench vices and valve operating screws.
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Buttress Thread The profile of this thread is a combination of square and V- threads. It combines the low frictional of square and ability to transmit power of square thread and the strength of V ? thread. It is used to transmit load in uni-direction. These threads are used in screw press, vices.
Knuckle Thread It is also a modification of square thread. The sharp corners of square thread are rounded off. This thread is used where heavy wear rough use is expected. The thread can be rolled or cast easily. It is used in railway carriage coupling screws, light bulbs and sockets, bottle caps etc and also objects made of brittle materials as glass, plastic, porcelains etc.
Types of thread profiles
Keys Keys are machine elements used to prevent relative rotational movement between a shaft and the parts mounted on it, such as pulleys, gears, wheels, couplings, etc. for making the joint, keyways are cut on the surface of the shaft and in the hub of the part to be mounted. After positioning the part on the shaft such that, both the keyways are properly aligned, the key is driven from the end, resulting in a firm joint. For mounting a part at any intermediate location on the shaft, first the key is firmly placed in the keyways of the shaft and then the part to be mounted is slid from one end of the shaft, till it is fully engaged with the key. Keys are classified into three types. 1. Saddle keys I. flat saddle key II. hollow saddle key
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2. Sunk keys I. taper sunk keys II. parallel sunk keys III. woodruff keys 3. Round keys
Types of keys
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Bolt and nuts A bolt and nut in combination is a fastening device used to hold two parts together. The body of the bolt, called shank is cylindrical in form, the head; square or hexagonal in shape, is formed by forging. Screw threads are cut on the other end of the shank. Nuts in general are square or hexagonal in shape. The nuts with internal threads engage with the corresponding size of the external threads of the bolt. However, there are other forms of nuts used to suit specific requirements. For nuts, hexagonal shape is preferred to the square one, as it is easy to tighten even in a limited space. This is because, with only one-sixth of a turn, the spanner can be reintroduced in the same position. However, square nuts are used when frequent loosening and tightening is required. The sharp corners on the head of bolts and nuts are removed by chamfering. Empirical portions of hexagonal and square head bolt & nut detail proportion Nominal diameter d = size of bolt or nut, mm Width across flats s = 1.5d+3 mm Width across corners e = 2d Thickness of bolt head k = 0.8d Thickness of nut, n = 0.9d Root diameter, d1 = d - (2 ? depth of thread) Length of the bolt L = as specified Thread length b = 2d+6mm (for l<150mm) = 2d+12mm (for l>150mm) Chamfer of bolt end, Z = (depth of thread ? 45 0 ) or =0.1d Chamfer angle of bolt head & nut 30 0
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1.5 Limits, fits and tolerances Limit System Following are some of the terms used in the limit system: Tolerance: The permissible variation of a size is called tolerance. It is the difference between the maximum and minimum permissible limits of the given size. If the variation is provided on one side of the basic size, it is termed as unilateral tolerance. Similarly, if the variation is provided on both sides of the basic size, it is known as bilateral tolerance. Limits: The two extreme permissible sizes between which the actual size is contained are called limits. The maximum size is called the upper limit and the minimum size is called the lower limit. Deviation: It is the algebraic difference between a size (actual, maximum, etc.) and the corresponding basic size. Actual deviation: It is the algebraic difference between the actual size and the corresponding basic size. Upper deviation: It is the algebraic difference between the maximum limit of the size and the corresponding basic size. Lower deviation: It is the algebraic difference between the minimum limit of the size and the corresponding basic size. Allowance: It is the dimensional difference between the maximum material limits of the mating parts, intentionally provided to obtain the desired class of fit. If the allowance is positive, it will result in minimum clearance between the mating parts and if the allowance is negative, it will result in maximum interference. Basic Size: It is determined solely from design calculations. If the strength and stiffness requirements need a 50mm diameter shaft, then 50mm is the basic shaft size. If it has to fit into a hole, then 50 mm is the basic size of the hole. Here, the two limit dimensions of the shaft are deviating in the negative direction with respect to the basic size and those of the hole in the positive direction. The line corresponding to the basic size is called the zero line or line of zero deviation.
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Fits The relation between two mating parts is known as a fit. Depending upon the actual limits of the hole or shaft sizes, fits may be classified as clearance fit, transition fit and interference fit.
Clearance Fit: It is a fit that gives a clearance between the two mating parts. minimum clearance: It is the difference between the minimum size of the hole and the maximum size of the shaft in a clearance fit. maximum clearance: It is the difference between the maximum size of the hole and the minimum size of the shaft in a clearance or transition fit. The fit between the shaft and hole in Fig. is a clearance fit that permits a minimum clearance (allowance) value of 29.95 ? 29.90 = + 0.05 mm and a maximum clearance of + 0.15 mm.
Transition Fit: This fit may result in either interference or a clearance, depending upon the actual values of the tolerance of individual parts. The shaft in Fig. may be either smaller or larger than the hole and still be within the prescribed tolerances. It results in a clearance fit, when shaft diameter is 29.95 and hole diameter is 30.05 (+ 0.10 mm) and interference fit, when shaft diameter is 30.00 and hole diameter 29.95 (? 0.05 mm).
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Interference fit: If the difference between the hole and shaft sizes is negative before assembly; an interference fit is obtained. minimum interference: It is the magnitude of the difference (negative) between the maximum size of the hole and the minimum size of the shaft in an interference fit before assembly. maximum interference: It is the magnitude of the difference between the minimum size of the hole and the maximum size of the shaft in an interference or a transition fit before assembly. The shaft in fig. is larger than the hole, so it requires a press fit, which has an effect similar to welding of two parts. The value of minimum interference is 30.25 ? 30.30 = ? 0.05 mm and maximum interference is 30.15 ? 30.40 = ? 0.25 mm.
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Schematic representation of fits:
Tolerance It is impossible to make anything to an exact size, therefore it is essential to allow a definite tolerance or permissible variation on every specified dimension. Tolerances are specified because ? Variations in properties of the material being machined introduce errors. ? The production machines themselves may have some inherent inaccuracies. ? It is impossible for an operator to make perfect settings. While setting up the tools and workpiece on the machine, some errors are likely to creep in.
Form variation: It is a variation of the actual condition of a form feature (surface, line) from geometrically ideal form. Position variation: It is a variation of the actual position of the form feature from the geometrically ideal position, with reference to another form (datum) feature. Geometrical tolerance: Geometrical tolerance is defined as the maximum permissible overall variation of form or position of a feature.
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Geometrical tolerances are used, (i) to specify the required accuracy in controlling the form of a feature, (ii) to ensure correct functional positioning of the feature, (iii) to ensure the interchangeability of components, and (iv) to facilitate the assembly of mating components. Tolerance zone: It is an imaginary area or volume within which the controlled feature of the manufactured component must be completely contained Datum: It is a theoretically exact geometric reference (such as axes, planes, straight lines, etc.) to which the tolerance features are related. Datum feature: A datum feature is a feature of a part, such as an edge, surface, or a hole, which forms the basis for a datum or is used to establish its location
Datum triangle: The datums are indicated by a leader line, terminating in a filled or an open triangle. Datum letter: To identify a datum for reference purposes, a capital letter is enclosed in a frame, connected to the datum triangle.
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Expt. No.02 INTRODUCTION TO CADD CADD is an electronic tool that enables us to make quick and accurate drawings. CADD has number of advantages over drawings created on a drawing board. Electronic drawings can be modified quite easily and can be represented in a variety of formats. CADD extends its power to yet another branch of engineering called computer aided manufacturing (CAM).CADD and manufacturing program are often integrated into one system called CAD-CAM. This system import CADD drawings into CAM program to automate the manufacturing process. When the design is finalized, the drawings are brought into a CAD-CAM system that uses numerical data from the CADD drawing for actual manufacturing. There is separate category of programs called Computer Aided Engineering (CAE) that can use CADD drawing for engineering analysis. The CAE programs have a number of applications in Structural Design, Civil Engineering, Mechanical Engineering and Electrical Engineering. The Mechanical engineer can test a machine assembly and also a prototype electronic model and test it without building a physical model. We can do amazing things with CADD that we never thought possible while creating drawings with pen or pencil. The following are some of the important capabilities that make CADD a powerful tool. ? Presentations ? Flexibility in editing ? Unit and accuracy levels ? Storage and access for drawings ? Sharing CADD drawings Presentations There are a number of ready-made presentations symbols available in CADD that can be used to enhance the look of drawings. In addition to prepare impressive presentations on paper, we can use CADD to make an on-screen presentations. Advanced CADD programs ever allow us to create an animated image. Flexibility in editing CADD allows us to work with great accuracy. If we need to create highly accuracy geometric shapes, CADD is the answer. It can help avoid time-consuming mathematical calculations. Unit and accuracy level We can work with as high precession as 1/1000 th of an inch. Storage and access of drawing A computer electronic filing system has the following advantages over the traditional filing system.
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? It is quick and convenient to organize CADD drawing in a computer. ? It enables us to create a highly organized environment. ? An electronic drawing never gets old and faded. Sharing CADD Drawing The electronic drawing can be shared by a number of users, allowing them to Co-ordinate projects and work as a team. This is accomplished by connecting different computer via a network.
About AutoCAD
AutoCAD is a Computer Aided Design (CAD) program used by just about every Engineering and Design office in the world. Although there are alternative CAD packages, AutoCAD is by far the most widely used system. Autodesk's AutoCAD is the industry leader in CAD packages. Used by Civil Engineers, Architects, Mechanical and Electrical Engineers, Aeronautical Engineers plus many other disciplines. There have been several versions of AutoCAD over the years, with each new version introducing new and more powerful features than its predecessor. The latest version of AutoCAD (at the time of writing) is AutoCAD 2011. Any courses, whether through community colleges or online universities, that are related to Engineering or Architecture should be considered incomplete if they do not introduce students to AutoCAD. Accurate, scale drawings can be created and published using AutoCAD powerful features. 3D 'models' can also be created giving the designer absolute control over the design from start to finish. The computerized model can be viewed through a 360? angle, and even 'rendered' with a texture on screen to give an idea of the finished product. Co-ordinate system
AutoCAD uses points to determine where an object is located. There is an origin where it begins counting from. This point is (0,0). Every object is located in relation to the origin. If we were to draw a line straight out to the right from
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the origin, this would be considered the positive X-axis. If we were to draw a line straight up, this would be the positive Y-axis. The picture above shows a point located at (9, 6). This means that the point is 9 units over in the X- axis and 6 units up in the Y-axis. When we are working with points, X always comes first. The other point shown is (-10,-4). This means that the point is 10 units in the negative X-axis (left) and 4 units in the negative Y-axis (down).
A line has two points, a start point and an end point. AutoCAD works with the points to display the line on the screen. Most of the time we will not have an indication of where the origin is. We may need to draw a line from the endpoint of an existing line. To do this we use relative points. These work the same way, but we have to add the @ symbol (shift+2) to tell AutoCAD that this next point is relative from the last point entered. i.e. 1. ABSOLUTE POINTS are exact points on the drawing space. 2. RELATIVE POINTS are relative to an OBJECT on the drawing space Angular Measurement AutoCAD measures angles in a particular way also.
When drawing lines at an angle, we have to begin measuring the angle from 0 degrees, which is at the 3 o'clock position. If we drew a line at 90 degrees, it would go straight up. The example shows a line drawn at +300 degrees (270+30), or -60 degrees.
Entering Points in AutoCAD We can enter points directly on the command line using three different systems. The one we use will depend on which is more applicable for the situation. The three systems are as follows:
ABSOLUTE CO-ORDINATES - Using this method, we enter the points as they relate to the origin of the WCS. To enter a point just enters in the exact point as X, Y.
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RELATIVE CO-ORDINATES - This allows us to enter points in relation to the first point we have entered. After we've entered one point, the next would be entered as @X, Y. This means that AutoCAD will draw a line from the first point to another point X units over and Y units up relative to the previous point. POLAR CO-ORDINATES - We would use this system if we know that we want to draw a line a certain distance at a particular angle. We would enter this as @D@10<90 will draw a line 10 units straight up from the first point. The three ways of entering co-ordinates shown above are the ONLY way AutoCAD accepts input. First decide which style we need to use, and then enter as shown. Remember that X is always before Y (alphabetical). Don't forget the '@' symbol when we are entering relative points. AutoCAD Basics Application Button - This button displays commands for printing, saving, drawing utilities and other non-drawing tool. Quick Access Toolbar - This is for quick access to common commands like New, Open, Save, Plot Filename - The name of the current file we are working on. Search Bar - Search for text in were drawing or search the help files. Ribbon - The Ribbon has most of the commands/tools that we will use while we are working. Tabs - A series of Tabs make up the Ribbon (Home, Insert, Manage, etc) and organize the Tools into common groups. Panels - Contain a group of tools Tools - These are the icon that starts the commands we use to draw, modify, etc. Tool Tip - If we however mouse over a tool, a tool tip will appear to give us more information. Hold it longer for more info. Drawing Space - These is where we draw were designs. Command line - When we type a command, we will see it here. AutoCAD uses this space to 'prompt' us for information. It will give us a lot of information and tell us where we are in the command. Status bar - This allows seeing and changing different modes of drawing such as Ortho, Osnaps, Grid, Otrack, etc. We can right click this area to toggle between icons and text for this area.
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Basic Drawing Commands for Autocad
Measuring Commands
GRID (F7): Displays a grid of dots at a desired spacing on the screen. Command: GRID (enter) On/Off/Tick spacing(x)/Aspect: (enter value) (enter)
SNAP (F9): Specifies a "round off" interval so that points entered with the mouse can be locked into alignment with the grid spacing. Command: SNAP (enter) On/Off/Value/Aspect/Rotate/Style: (enter value) (enter) Basic Draw Commands CIRCLE (C): Draws circles of any size. Command: Circle (enter) 3P/2P/TTR/
: (pick a center point) Diameter or : (Pick a point on the circle) LINE (L): Draws straight lines between two points Command: LINE (enter) From Point: (pick a point using the mouse) To Point: (Pick a point using the mouse) To Point: (Press return to end the command) ARC (A): Draws an arc (any part of a circle or curve) through three known points. Command: ARC (enter) Center/ < Start point > : (pick the first point on the arc) Center/End/ < Second point >:C Center: (pick the arc's center point) Angle/Length of chord/ : (pick the arc endpoint) Display Commands LIMITS: Sets the size of the drawing paper. For size "A" drawing paper the limits should be set for 10.5 x 8. Command: LIMITS (enter) On/Off/Lower left corner <0.0000> (enter) Upper right corner: 10.5,8 (enter) FirstRanker.com - FirstRanker's Choice
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DEPARTMENT OF MECHANICAL ENGINEERING
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
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College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
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PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
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To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
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ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
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Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
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Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
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The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
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The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
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1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
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Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power
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Terms and Nomenclature
1. Crest: It is the peak edge of a screw thread that connects the adjacent flanks at the top. 2. Root: It is the bottom edge of the thread that connects the adjacent flanks at the bottom. 3. Flank or side: It is the straight portion of the surface, on either side of the screw thread. 4. Angle of the thread: It is the angle included between the sides of two adjacent threads measured on an axial plane. 5. Depth of the thread: It is the distance between the crest and the root measured at Right angle to the axis. It is equal to half the difference between the outer diameter and the core diameter. 6. Major diameter or outside diameter: It is the diameter of the imaginary coaxial cylinder, which would bind the crests of an external or internal thread. 7. Minor or core or root diameter: It is the diameter of the imaginary coaxial cylinder; this would bind the roots of an external thread or of an internal thread. 8. Pitch diameter: It is the diameter of the imaginary coaxial cylinder that can be passed so as to cut the thread, that the width of the cut thread will be equal to the Width of the groove. 9. Pitch: It is the axial distance between a point on one thread and the corresponding Point on the next thread. It may be indicated as the distance from crest or from root of two adjacent threads. 10. Lead: It is the distance measured parallel to the axis from a point on a thread to the corresponding point on the same thread for one complete revolution. In other words, it is axial distance a screw advances in one revolution. 11. External thread: It is the thread on the outside surface of a member such as bolt, studs or screw. 12. Internal thread: It is the thread on the inside surface of a member such as nut or threaded hole. 13. Right hand thread: Right hand thread if turned clockwise direction advances into a threaded hole. It abbreviated as RH. 14. Left hand thread: Left hand thread if turned anticlockwise direction advances into a threaded hole. It abbreviated as LH.
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V- THREADS British standard whit worth thread (BSW) This thread was introduced by Sir Joseph whit worth, and was standardized as British standard thread. It has a thread angle of 55 degree and is rounded equally at crest and roots. British Association threads (B.A Threads) The angle between flanks is 47.5 degree. These threads are to supplement BSW and have fine pitches. They are used on screws for precision work. American standard threads (or) sellers thread The thread angle is 60 degree and both the crests and roots are kept flat. The sellers thread has been in use in USA and Canada. Unified screw threads The countries UK, U.S.A and Canada came to an arrangement for a common screw thread system with the included angle of 60 degree and designated as unified screw thread in the year 1949. The thread on the bolt is rounded off at the crest and root and the thread in the nut is rounded off at the root but the crest is left flat. This thread is very important in the motor and aeroplane industries and in chemical engineering. Unified thread can be either coarse (UNC) or fine (UNF) and unified national extra fine (UEF). ISO Metric Thread This is Indian standard thread for ISO (International Standard Organization). The included angle is 60 0 and the crests are flat and roots are round. Metric threads are grouped into diameter pitch combination differentiated by the pitch applied to specific diameters. There are coarse, constant, fine pitch series available. ISO metric threads are defined by nominal size (Basic major diameter) and pitch both expressed in millimeters. for example, a 10mm diameter, 1.25 pitches is expressed as M10?1.25. SQUARE THREADS Basic square thread The sides of these threads are normal to the axis and parallel to each other. The depth and the thickness of the thread are equal to half pitch. A square thread is designated by the letter SQ followed by nominal diameter pitch. For example a square thread of nominal diameter 30mm and pitch 6mm is designated as SQ 30?6. Acme Thread It is a modified form of square thread. It is easier to cut and is much stronger than square thread. It has a 29 0
thread angle. This inclined sides of the thread facilitate quick and early engagement and disengagement. It is used for power screws like lead screw of lathe, jackscrews, bench vices and valve operating screws.
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Buttress Thread The profile of this thread is a combination of square and V- threads. It combines the low frictional of square and ability to transmit power of square thread and the strength of V ? thread. It is used to transmit load in uni-direction. These threads are used in screw press, vices.
Knuckle Thread It is also a modification of square thread. The sharp corners of square thread are rounded off. This thread is used where heavy wear rough use is expected. The thread can be rolled or cast easily. It is used in railway carriage coupling screws, light bulbs and sockets, bottle caps etc and also objects made of brittle materials as glass, plastic, porcelains etc.
Types of thread profiles
Keys Keys are machine elements used to prevent relative rotational movement between a shaft and the parts mounted on it, such as pulleys, gears, wheels, couplings, etc. for making the joint, keyways are cut on the surface of the shaft and in the hub of the part to be mounted. After positioning the part on the shaft such that, both the keyways are properly aligned, the key is driven from the end, resulting in a firm joint. For mounting a part at any intermediate location on the shaft, first the key is firmly placed in the keyways of the shaft and then the part to be mounted is slid from one end of the shaft, till it is fully engaged with the key. Keys are classified into three types. 1. Saddle keys I. flat saddle key II. hollow saddle key
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2. Sunk keys I. taper sunk keys II. parallel sunk keys III. woodruff keys 3. Round keys
Types of keys
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Bolt and nuts A bolt and nut in combination is a fastening device used to hold two parts together. The body of the bolt, called shank is cylindrical in form, the head; square or hexagonal in shape, is formed by forging. Screw threads are cut on the other end of the shank. Nuts in general are square or hexagonal in shape. The nuts with internal threads engage with the corresponding size of the external threads of the bolt. However, there are other forms of nuts used to suit specific requirements. For nuts, hexagonal shape is preferred to the square one, as it is easy to tighten even in a limited space. This is because, with only one-sixth of a turn, the spanner can be reintroduced in the same position. However, square nuts are used when frequent loosening and tightening is required. The sharp corners on the head of bolts and nuts are removed by chamfering. Empirical portions of hexagonal and square head bolt & nut detail proportion Nominal diameter d = size of bolt or nut, mm Width across flats s = 1.5d+3 mm Width across corners e = 2d Thickness of bolt head k = 0.8d Thickness of nut, n = 0.9d Root diameter, d1 = d - (2 ? depth of thread) Length of the bolt L = as specified Thread length b = 2d+6mm (for l<150mm) = 2d+12mm (for l>150mm) Chamfer of bolt end, Z = (depth of thread ? 45 0 ) or =0.1d Chamfer angle of bolt head & nut 30 0
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1.5 Limits, fits and tolerances Limit System Following are some of the terms used in the limit system: Tolerance: The permissible variation of a size is called tolerance. It is the difference between the maximum and minimum permissible limits of the given size. If the variation is provided on one side of the basic size, it is termed as unilateral tolerance. Similarly, if the variation is provided on both sides of the basic size, it is known as bilateral tolerance. Limits: The two extreme permissible sizes between which the actual size is contained are called limits. The maximum size is called the upper limit and the minimum size is called the lower limit. Deviation: It is the algebraic difference between a size (actual, maximum, etc.) and the corresponding basic size. Actual deviation: It is the algebraic difference between the actual size and the corresponding basic size. Upper deviation: It is the algebraic difference between the maximum limit of the size and the corresponding basic size. Lower deviation: It is the algebraic difference between the minimum limit of the size and the corresponding basic size. Allowance: It is the dimensional difference between the maximum material limits of the mating parts, intentionally provided to obtain the desired class of fit. If the allowance is positive, it will result in minimum clearance between the mating parts and if the allowance is negative, it will result in maximum interference. Basic Size: It is determined solely from design calculations. If the strength and stiffness requirements need a 50mm diameter shaft, then 50mm is the basic shaft size. If it has to fit into a hole, then 50 mm is the basic size of the hole. Here, the two limit dimensions of the shaft are deviating in the negative direction with respect to the basic size and those of the hole in the positive direction. The line corresponding to the basic size is called the zero line or line of zero deviation.
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Fits The relation between two mating parts is known as a fit. Depending upon the actual limits of the hole or shaft sizes, fits may be classified as clearance fit, transition fit and interference fit.
Clearance Fit: It is a fit that gives a clearance between the two mating parts. minimum clearance: It is the difference between the minimum size of the hole and the maximum size of the shaft in a clearance fit. maximum clearance: It is the difference between the maximum size of the hole and the minimum size of the shaft in a clearance or transition fit. The fit between the shaft and hole in Fig. is a clearance fit that permits a minimum clearance (allowance) value of 29.95 ? 29.90 = + 0.05 mm and a maximum clearance of + 0.15 mm.
Transition Fit: This fit may result in either interference or a clearance, depending upon the actual values of the tolerance of individual parts. The shaft in Fig. may be either smaller or larger than the hole and still be within the prescribed tolerances. It results in a clearance fit, when shaft diameter is 29.95 and hole diameter is 30.05 (+ 0.10 mm) and interference fit, when shaft diameter is 30.00 and hole diameter 29.95 (? 0.05 mm).
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Interference fit: If the difference between the hole and shaft sizes is negative before assembly; an interference fit is obtained. minimum interference: It is the magnitude of the difference (negative) between the maximum size of the hole and the minimum size of the shaft in an interference fit before assembly. maximum interference: It is the magnitude of the difference between the minimum size of the hole and the maximum size of the shaft in an interference or a transition fit before assembly. The shaft in fig. is larger than the hole, so it requires a press fit, which has an effect similar to welding of two parts. The value of minimum interference is 30.25 ? 30.30 = ? 0.05 mm and maximum interference is 30.15 ? 30.40 = ? 0.25 mm.
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Schematic representation of fits:
Tolerance It is impossible to make anything to an exact size, therefore it is essential to allow a definite tolerance or permissible variation on every specified dimension. Tolerances are specified because ? Variations in properties of the material being machined introduce errors. ? The production machines themselves may have some inherent inaccuracies. ? It is impossible for an operator to make perfect settings. While setting up the tools and workpiece on the machine, some errors are likely to creep in.
Form variation: It is a variation of the actual condition of a form feature (surface, line) from geometrically ideal form. Position variation: It is a variation of the actual position of the form feature from the geometrically ideal position, with reference to another form (datum) feature. Geometrical tolerance: Geometrical tolerance is defined as the maximum permissible overall variation of form or position of a feature.
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Geometrical tolerances are used, (i) to specify the required accuracy in controlling the form of a feature, (ii) to ensure correct functional positioning of the feature, (iii) to ensure the interchangeability of components, and (iv) to facilitate the assembly of mating components. Tolerance zone: It is an imaginary area or volume within which the controlled feature of the manufactured component must be completely contained Datum: It is a theoretically exact geometric reference (such as axes, planes, straight lines, etc.) to which the tolerance features are related. Datum feature: A datum feature is a feature of a part, such as an edge, surface, or a hole, which forms the basis for a datum or is used to establish its location
Datum triangle: The datums are indicated by a leader line, terminating in a filled or an open triangle. Datum letter: To identify a datum for reference purposes, a capital letter is enclosed in a frame, connected to the datum triangle.
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Expt. No.02 INTRODUCTION TO CADD CADD is an electronic tool that enables us to make quick and accurate drawings. CADD has number of advantages over drawings created on a drawing board. Electronic drawings can be modified quite easily and can be represented in a variety of formats. CADD extends its power to yet another branch of engineering called computer aided manufacturing (CAM).CADD and manufacturing program are often integrated into one system called CAD-CAM. This system import CADD drawings into CAM program to automate the manufacturing process. When the design is finalized, the drawings are brought into a CAD-CAM system that uses numerical data from the CADD drawing for actual manufacturing. There is separate category of programs called Computer Aided Engineering (CAE) that can use CADD drawing for engineering analysis. The CAE programs have a number of applications in Structural Design, Civil Engineering, Mechanical Engineering and Electrical Engineering. The Mechanical engineer can test a machine assembly and also a prototype electronic model and test it without building a physical model. We can do amazing things with CADD that we never thought possible while creating drawings with pen or pencil. The following are some of the important capabilities that make CADD a powerful tool. ? Presentations ? Flexibility in editing ? Unit and accuracy levels ? Storage and access for drawings ? Sharing CADD drawings Presentations There are a number of ready-made presentations symbols available in CADD that can be used to enhance the look of drawings. In addition to prepare impressive presentations on paper, we can use CADD to make an on-screen presentations. Advanced CADD programs ever allow us to create an animated image. Flexibility in editing CADD allows us to work with great accuracy. If we need to create highly accuracy geometric shapes, CADD is the answer. It can help avoid time-consuming mathematical calculations. Unit and accuracy level We can work with as high precession as 1/1000 th of an inch. Storage and access of drawing A computer electronic filing system has the following advantages over the traditional filing system.
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? It is quick and convenient to organize CADD drawing in a computer. ? It enables us to create a highly organized environment. ? An electronic drawing never gets old and faded. Sharing CADD Drawing The electronic drawing can be shared by a number of users, allowing them to Co-ordinate projects and work as a team. This is accomplished by connecting different computer via a network.
About AutoCAD
AutoCAD is a Computer Aided Design (CAD) program used by just about every Engineering and Design office in the world. Although there are alternative CAD packages, AutoCAD is by far the most widely used system. Autodesk's AutoCAD is the industry leader in CAD packages. Used by Civil Engineers, Architects, Mechanical and Electrical Engineers, Aeronautical Engineers plus many other disciplines. There have been several versions of AutoCAD over the years, with each new version introducing new and more powerful features than its predecessor. The latest version of AutoCAD (at the time of writing) is AutoCAD 2011. Any courses, whether through community colleges or online universities, that are related to Engineering or Architecture should be considered incomplete if they do not introduce students to AutoCAD. Accurate, scale drawings can be created and published using AutoCAD powerful features. 3D 'models' can also be created giving the designer absolute control over the design from start to finish. The computerized model can be viewed through a 360? angle, and even 'rendered' with a texture on screen to give an idea of the finished product. Co-ordinate system
AutoCAD uses points to determine where an object is located. There is an origin where it begins counting from. This point is (0,0). Every object is located in relation to the origin. If we were to draw a line straight out to the right from
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the origin, this would be considered the positive X-axis. If we were to draw a line straight up, this would be the positive Y-axis. The picture above shows a point located at (9, 6). This means that the point is 9 units over in the X- axis and 6 units up in the Y-axis. When we are working with points, X always comes first. The other point shown is (-10,-4). This means that the point is 10 units in the negative X-axis (left) and 4 units in the negative Y-axis (down).
A line has two points, a start point and an end point. AutoCAD works with the points to display the line on the screen. Most of the time we will not have an indication of where the origin is. We may need to draw a line from the endpoint of an existing line. To do this we use relative points. These work the same way, but we have to add the @ symbol (shift+2) to tell AutoCAD that this next point is relative from the last point entered. i.e. 1. ABSOLUTE POINTS are exact points on the drawing space. 2. RELATIVE POINTS are relative to an OBJECT on the drawing space Angular Measurement AutoCAD measures angles in a particular way also.
When drawing lines at an angle, we have to begin measuring the angle from 0 degrees, which is at the 3 o'clock position. If we drew a line at 90 degrees, it would go straight up. The example shows a line drawn at +300 degrees (270+30), or -60 degrees.
Entering Points in AutoCAD We can enter points directly on the command line using three different systems. The one we use will depend on which is more applicable for the situation. The three systems are as follows:
ABSOLUTE CO-ORDINATES - Using this method, we enter the points as they relate to the origin of the WCS. To enter a point just enters in the exact point as X, Y.
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RELATIVE CO-ORDINATES - This allows us to enter points in relation to the first point we have entered. After we've entered one point, the next would be entered as @X, Y. This means that AutoCAD will draw a line from the first point to another point X units over and Y units up relative to the previous point. POLAR CO-ORDINATES - We would use this system if we know that we want to draw a line a certain distance at a particular angle. We would enter this as @D@10<90 will draw a line 10 units straight up from the first point. The three ways of entering co-ordinates shown above are the ONLY way AutoCAD accepts input. First decide which style we need to use, and then enter as shown. Remember that X is always before Y (alphabetical). Don't forget the '@' symbol when we are entering relative points. AutoCAD Basics Application Button - This button displays commands for printing, saving, drawing utilities and other non-drawing tool. Quick Access Toolbar - This is for quick access to common commands like New, Open, Save, Plot Filename - The name of the current file we are working on. Search Bar - Search for text in were drawing or search the help files. Ribbon - The Ribbon has most of the commands/tools that we will use while we are working. Tabs - A series of Tabs make up the Ribbon (Home, Insert, Manage, etc) and organize the Tools into common groups. Panels - Contain a group of tools Tools - These are the icon that starts the commands we use to draw, modify, etc. Tool Tip - If we however mouse over a tool, a tool tip will appear to give us more information. Hold it longer for more info. Drawing Space - These is where we draw were designs. Command line - When we type a command, we will see it here. AutoCAD uses this space to 'prompt' us for information. It will give us a lot of information and tell us where we are in the command. Status bar - This allows seeing and changing different modes of drawing such as Ortho, Osnaps, Grid, Otrack, etc. We can right click this area to toggle between icons and text for this area.
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Basic Drawing Commands for Autocad
Measuring Commands
GRID (F7): Displays a grid of dots at a desired spacing on the screen. Command: GRID (enter) On/Off/Tick spacing(x)/Aspect: (enter value) (enter)
SNAP (F9): Specifies a "round off" interval so that points entered with the mouse can be locked into alignment with the grid spacing. Command: SNAP (enter) On/Off/Value/Aspect/Rotate/Style: (enter value) (enter) Basic Draw Commands CIRCLE (C): Draws circles of any size. Command: Circle (enter) 3P/2P/TTR/
: (pick a center point) Diameter or : (Pick a point on the circle) LINE (L): Draws straight lines between two points Command: LINE (enter) From Point: (pick a point using the mouse) To Point: (Pick a point using the mouse) To Point: (Press return to end the command) ARC (A): Draws an arc (any part of a circle or curve) through three known points. Command: ARC (enter) Center/ < Start point > : (pick the first point on the arc) Center/End/ < Second point >:C Center: (pick the arc's center point) Angle/Length of chord/ : (pick the arc endpoint) Display Commands LIMITS: Sets the size of the drawing paper. For size "A" drawing paper the limits should be set for 10.5 x 8. Command: LIMITS (enter) On/Off/Lower left corner <0.0000> (enter) Upper right corner: 10.5,8 (enter)
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ZOOM (Z): Enlarges or reduces the display of a drawing. PAN: Allows we to move were view point around the drawing without changing the magnification factor. Command: PAN (enter)
Editing Commands CHANGE: Alters properties of selected objects Command: CHANGE (enter) Select objects or window or Last (select objects to be changed) Properties/: (type P) Change what property (Color/Elev/ Layer/L Type/Thickness)? (Type Layer) New Layer: (enter new layer name and press enter)
ERASE (E): Erases entities from the drawing. Command: ERASE (enter) Select objects or Window or Last: (Select objects to be erased and press enter when finished)
TRIM (TR): Trims a line to end precisely at a cutting edge. Command: Trim (enter) Select cutting edge(s)... Select Objects (pick the line which represents the cutting edge of line in which objects will be trimmed to)(press enter when finished selecting cutting edges)trim>/Undo: (pick the line(s) that need to be trimmed). Creating Layers LAYER: Creates named drawing layers and assigns color and line type properties to those layers. Command: LAYER (enter) A Layer & Line type Properties dialog box will be displayed. To add a new layer, pick the new button. A new layer listing appears, using a default name of Layer1. The layer name can be changed by highlighting the layer name. Colors and Line types can be assigned to each new layer by picking the color box to assign a color and picking the line type box to assign a line type.
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
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College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
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PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
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To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
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ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
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Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
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Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
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The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
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The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
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1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
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Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power
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Terms and Nomenclature
1. Crest: It is the peak edge of a screw thread that connects the adjacent flanks at the top. 2. Root: It is the bottom edge of the thread that connects the adjacent flanks at the bottom. 3. Flank or side: It is the straight portion of the surface, on either side of the screw thread. 4. Angle of the thread: It is the angle included between the sides of two adjacent threads measured on an axial plane. 5. Depth of the thread: It is the distance between the crest and the root measured at Right angle to the axis. It is equal to half the difference between the outer diameter and the core diameter. 6. Major diameter or outside diameter: It is the diameter of the imaginary coaxial cylinder, which would bind the crests of an external or internal thread. 7. Minor or core or root diameter: It is the diameter of the imaginary coaxial cylinder; this would bind the roots of an external thread or of an internal thread. 8. Pitch diameter: It is the diameter of the imaginary coaxial cylinder that can be passed so as to cut the thread, that the width of the cut thread will be equal to the Width of the groove. 9. Pitch: It is the axial distance between a point on one thread and the corresponding Point on the next thread. It may be indicated as the distance from crest or from root of two adjacent threads. 10. Lead: It is the distance measured parallel to the axis from a point on a thread to the corresponding point on the same thread for one complete revolution. In other words, it is axial distance a screw advances in one revolution. 11. External thread: It is the thread on the outside surface of a member such as bolt, studs or screw. 12. Internal thread: It is the thread on the inside surface of a member such as nut or threaded hole. 13. Right hand thread: Right hand thread if turned clockwise direction advances into a threaded hole. It abbreviated as RH. 14. Left hand thread: Left hand thread if turned anticlockwise direction advances into a threaded hole. It abbreviated as LH.
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V- THREADS British standard whit worth thread (BSW) This thread was introduced by Sir Joseph whit worth, and was standardized as British standard thread. It has a thread angle of 55 degree and is rounded equally at crest and roots. British Association threads (B.A Threads) The angle between flanks is 47.5 degree. These threads are to supplement BSW and have fine pitches. They are used on screws for precision work. American standard threads (or) sellers thread The thread angle is 60 degree and both the crests and roots are kept flat. The sellers thread has been in use in USA and Canada. Unified screw threads The countries UK, U.S.A and Canada came to an arrangement for a common screw thread system with the included angle of 60 degree and designated as unified screw thread in the year 1949. The thread on the bolt is rounded off at the crest and root and the thread in the nut is rounded off at the root but the crest is left flat. This thread is very important in the motor and aeroplane industries and in chemical engineering. Unified thread can be either coarse (UNC) or fine (UNF) and unified national extra fine (UEF). ISO Metric Thread This is Indian standard thread for ISO (International Standard Organization). The included angle is 60 0 and the crests are flat and roots are round. Metric threads are grouped into diameter pitch combination differentiated by the pitch applied to specific diameters. There are coarse, constant, fine pitch series available. ISO metric threads are defined by nominal size (Basic major diameter) and pitch both expressed in millimeters. for example, a 10mm diameter, 1.25 pitches is expressed as M10?1.25. SQUARE THREADS Basic square thread The sides of these threads are normal to the axis and parallel to each other. The depth and the thickness of the thread are equal to half pitch. A square thread is designated by the letter SQ followed by nominal diameter pitch. For example a square thread of nominal diameter 30mm and pitch 6mm is designated as SQ 30?6. Acme Thread It is a modified form of square thread. It is easier to cut and is much stronger than square thread. It has a 29 0
thread angle. This inclined sides of the thread facilitate quick and early engagement and disengagement. It is used for power screws like lead screw of lathe, jackscrews, bench vices and valve operating screws.
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Buttress Thread The profile of this thread is a combination of square and V- threads. It combines the low frictional of square and ability to transmit power of square thread and the strength of V ? thread. It is used to transmit load in uni-direction. These threads are used in screw press, vices.
Knuckle Thread It is also a modification of square thread. The sharp corners of square thread are rounded off. This thread is used where heavy wear rough use is expected. The thread can be rolled or cast easily. It is used in railway carriage coupling screws, light bulbs and sockets, bottle caps etc and also objects made of brittle materials as glass, plastic, porcelains etc.
Types of thread profiles
Keys Keys are machine elements used to prevent relative rotational movement between a shaft and the parts mounted on it, such as pulleys, gears, wheels, couplings, etc. for making the joint, keyways are cut on the surface of the shaft and in the hub of the part to be mounted. After positioning the part on the shaft such that, both the keyways are properly aligned, the key is driven from the end, resulting in a firm joint. For mounting a part at any intermediate location on the shaft, first the key is firmly placed in the keyways of the shaft and then the part to be mounted is slid from one end of the shaft, till it is fully engaged with the key. Keys are classified into three types. 1. Saddle keys I. flat saddle key II. hollow saddle key
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2. Sunk keys I. taper sunk keys II. parallel sunk keys III. woodruff keys 3. Round keys
Types of keys
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Bolt and nuts A bolt and nut in combination is a fastening device used to hold two parts together. The body of the bolt, called shank is cylindrical in form, the head; square or hexagonal in shape, is formed by forging. Screw threads are cut on the other end of the shank. Nuts in general are square or hexagonal in shape. The nuts with internal threads engage with the corresponding size of the external threads of the bolt. However, there are other forms of nuts used to suit specific requirements. For nuts, hexagonal shape is preferred to the square one, as it is easy to tighten even in a limited space. This is because, with only one-sixth of a turn, the spanner can be reintroduced in the same position. However, square nuts are used when frequent loosening and tightening is required. The sharp corners on the head of bolts and nuts are removed by chamfering. Empirical portions of hexagonal and square head bolt & nut detail proportion Nominal diameter d = size of bolt or nut, mm Width across flats s = 1.5d+3 mm Width across corners e = 2d Thickness of bolt head k = 0.8d Thickness of nut, n = 0.9d Root diameter, d1 = d - (2 ? depth of thread) Length of the bolt L = as specified Thread length b = 2d+6mm (for l<150mm) = 2d+12mm (for l>150mm) Chamfer of bolt end, Z = (depth of thread ? 45 0 ) or =0.1d Chamfer angle of bolt head & nut 30 0
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1.5 Limits, fits and tolerances Limit System Following are some of the terms used in the limit system: Tolerance: The permissible variation of a size is called tolerance. It is the difference between the maximum and minimum permissible limits of the given size. If the variation is provided on one side of the basic size, it is termed as unilateral tolerance. Similarly, if the variation is provided on both sides of the basic size, it is known as bilateral tolerance. Limits: The two extreme permissible sizes between which the actual size is contained are called limits. The maximum size is called the upper limit and the minimum size is called the lower limit. Deviation: It is the algebraic difference between a size (actual, maximum, etc.) and the corresponding basic size. Actual deviation: It is the algebraic difference between the actual size and the corresponding basic size. Upper deviation: It is the algebraic difference between the maximum limit of the size and the corresponding basic size. Lower deviation: It is the algebraic difference between the minimum limit of the size and the corresponding basic size. Allowance: It is the dimensional difference between the maximum material limits of the mating parts, intentionally provided to obtain the desired class of fit. If the allowance is positive, it will result in minimum clearance between the mating parts and if the allowance is negative, it will result in maximum interference. Basic Size: It is determined solely from design calculations. If the strength and stiffness requirements need a 50mm diameter shaft, then 50mm is the basic shaft size. If it has to fit into a hole, then 50 mm is the basic size of the hole. Here, the two limit dimensions of the shaft are deviating in the negative direction with respect to the basic size and those of the hole in the positive direction. The line corresponding to the basic size is called the zero line or line of zero deviation.
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Fits The relation between two mating parts is known as a fit. Depending upon the actual limits of the hole or shaft sizes, fits may be classified as clearance fit, transition fit and interference fit.
Clearance Fit: It is a fit that gives a clearance between the two mating parts. minimum clearance: It is the difference between the minimum size of the hole and the maximum size of the shaft in a clearance fit. maximum clearance: It is the difference between the maximum size of the hole and the minimum size of the shaft in a clearance or transition fit. The fit between the shaft and hole in Fig. is a clearance fit that permits a minimum clearance (allowance) value of 29.95 ? 29.90 = + 0.05 mm and a maximum clearance of + 0.15 mm.
Transition Fit: This fit may result in either interference or a clearance, depending upon the actual values of the tolerance of individual parts. The shaft in Fig. may be either smaller or larger than the hole and still be within the prescribed tolerances. It results in a clearance fit, when shaft diameter is 29.95 and hole diameter is 30.05 (+ 0.10 mm) and interference fit, when shaft diameter is 30.00 and hole diameter 29.95 (? 0.05 mm).
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Interference fit: If the difference between the hole and shaft sizes is negative before assembly; an interference fit is obtained. minimum interference: It is the magnitude of the difference (negative) between the maximum size of the hole and the minimum size of the shaft in an interference fit before assembly. maximum interference: It is the magnitude of the difference between the minimum size of the hole and the maximum size of the shaft in an interference or a transition fit before assembly. The shaft in fig. is larger than the hole, so it requires a press fit, which has an effect similar to welding of two parts. The value of minimum interference is 30.25 ? 30.30 = ? 0.05 mm and maximum interference is 30.15 ? 30.40 = ? 0.25 mm.
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Schematic representation of fits:
Tolerance It is impossible to make anything to an exact size, therefore it is essential to allow a definite tolerance or permissible variation on every specified dimension. Tolerances are specified because ? Variations in properties of the material being machined introduce errors. ? The production machines themselves may have some inherent inaccuracies. ? It is impossible for an operator to make perfect settings. While setting up the tools and workpiece on the machine, some errors are likely to creep in.
Form variation: It is a variation of the actual condition of a form feature (surface, line) from geometrically ideal form. Position variation: It is a variation of the actual position of the form feature from the geometrically ideal position, with reference to another form (datum) feature. Geometrical tolerance: Geometrical tolerance is defined as the maximum permissible overall variation of form or position of a feature.
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Geometrical tolerances are used, (i) to specify the required accuracy in controlling the form of a feature, (ii) to ensure correct functional positioning of the feature, (iii) to ensure the interchangeability of components, and (iv) to facilitate the assembly of mating components. Tolerance zone: It is an imaginary area or volume within which the controlled feature of the manufactured component must be completely contained Datum: It is a theoretically exact geometric reference (such as axes, planes, straight lines, etc.) to which the tolerance features are related. Datum feature: A datum feature is a feature of a part, such as an edge, surface, or a hole, which forms the basis for a datum or is used to establish its location
Datum triangle: The datums are indicated by a leader line, terminating in a filled or an open triangle. Datum letter: To identify a datum for reference purposes, a capital letter is enclosed in a frame, connected to the datum triangle.
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Expt. No.02 INTRODUCTION TO CADD CADD is an electronic tool that enables us to make quick and accurate drawings. CADD has number of advantages over drawings created on a drawing board. Electronic drawings can be modified quite easily and can be represented in a variety of formats. CADD extends its power to yet another branch of engineering called computer aided manufacturing (CAM).CADD and manufacturing program are often integrated into one system called CAD-CAM. This system import CADD drawings into CAM program to automate the manufacturing process. When the design is finalized, the drawings are brought into a CAD-CAM system that uses numerical data from the CADD drawing for actual manufacturing. There is separate category of programs called Computer Aided Engineering (CAE) that can use CADD drawing for engineering analysis. The CAE programs have a number of applications in Structural Design, Civil Engineering, Mechanical Engineering and Electrical Engineering. The Mechanical engineer can test a machine assembly and also a prototype electronic model and test it without building a physical model. We can do amazing things with CADD that we never thought possible while creating drawings with pen or pencil. The following are some of the important capabilities that make CADD a powerful tool. ? Presentations ? Flexibility in editing ? Unit and accuracy levels ? Storage and access for drawings ? Sharing CADD drawings Presentations There are a number of ready-made presentations symbols available in CADD that can be used to enhance the look of drawings. In addition to prepare impressive presentations on paper, we can use CADD to make an on-screen presentations. Advanced CADD programs ever allow us to create an animated image. Flexibility in editing CADD allows us to work with great accuracy. If we need to create highly accuracy geometric shapes, CADD is the answer. It can help avoid time-consuming mathematical calculations. Unit and accuracy level We can work with as high precession as 1/1000 th of an inch. Storage and access of drawing A computer electronic filing system has the following advantages over the traditional filing system.
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? It is quick and convenient to organize CADD drawing in a computer. ? It enables us to create a highly organized environment. ? An electronic drawing never gets old and faded. Sharing CADD Drawing The electronic drawing can be shared by a number of users, allowing them to Co-ordinate projects and work as a team. This is accomplished by connecting different computer via a network.
About AutoCAD
AutoCAD is a Computer Aided Design (CAD) program used by just about every Engineering and Design office in the world. Although there are alternative CAD packages, AutoCAD is by far the most widely used system. Autodesk's AutoCAD is the industry leader in CAD packages. Used by Civil Engineers, Architects, Mechanical and Electrical Engineers, Aeronautical Engineers plus many other disciplines. There have been several versions of AutoCAD over the years, with each new version introducing new and more powerful features than its predecessor. The latest version of AutoCAD (at the time of writing) is AutoCAD 2011. Any courses, whether through community colleges or online universities, that are related to Engineering or Architecture should be considered incomplete if they do not introduce students to AutoCAD. Accurate, scale drawings can be created and published using AutoCAD powerful features. 3D 'models' can also be created giving the designer absolute control over the design from start to finish. The computerized model can be viewed through a 360? angle, and even 'rendered' with a texture on screen to give an idea of the finished product. Co-ordinate system
AutoCAD uses points to determine where an object is located. There is an origin where it begins counting from. This point is (0,0). Every object is located in relation to the origin. If we were to draw a line straight out to the right from
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the origin, this would be considered the positive X-axis. If we were to draw a line straight up, this would be the positive Y-axis. The picture above shows a point located at (9, 6). This means that the point is 9 units over in the X- axis and 6 units up in the Y-axis. When we are working with points, X always comes first. The other point shown is (-10,-4). This means that the point is 10 units in the negative X-axis (left) and 4 units in the negative Y-axis (down).
A line has two points, a start point and an end point. AutoCAD works with the points to display the line on the screen. Most of the time we will not have an indication of where the origin is. We may need to draw a line from the endpoint of an existing line. To do this we use relative points. These work the same way, but we have to add the @ symbol (shift+2) to tell AutoCAD that this next point is relative from the last point entered. i.e. 1. ABSOLUTE POINTS are exact points on the drawing space. 2. RELATIVE POINTS are relative to an OBJECT on the drawing space Angular Measurement AutoCAD measures angles in a particular way also.
When drawing lines at an angle, we have to begin measuring the angle from 0 degrees, which is at the 3 o'clock position. If we drew a line at 90 degrees, it would go straight up. The example shows a line drawn at +300 degrees (270+30), or -60 degrees.
Entering Points in AutoCAD We can enter points directly on the command line using three different systems. The one we use will depend on which is more applicable for the situation. The three systems are as follows:
ABSOLUTE CO-ORDINATES - Using this method, we enter the points as they relate to the origin of the WCS. To enter a point just enters in the exact point as X, Y.
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RELATIVE CO-ORDINATES - This allows us to enter points in relation to the first point we have entered. After we've entered one point, the next would be entered as @X, Y. This means that AutoCAD will draw a line from the first point to another point X units over and Y units up relative to the previous point. POLAR CO-ORDINATES - We would use this system if we know that we want to draw a line a certain distance at a particular angle. We would enter this as @D@10<90 will draw a line 10 units straight up from the first point. The three ways of entering co-ordinates shown above are the ONLY way AutoCAD accepts input. First decide which style we need to use, and then enter as shown. Remember that X is always before Y (alphabetical). Don't forget the '@' symbol when we are entering relative points. AutoCAD Basics Application Button - This button displays commands for printing, saving, drawing utilities and other non-drawing tool. Quick Access Toolbar - This is for quick access to common commands like New, Open, Save, Plot Filename - The name of the current file we are working on. Search Bar - Search for text in were drawing or search the help files. Ribbon - The Ribbon has most of the commands/tools that we will use while we are working. Tabs - A series of Tabs make up the Ribbon (Home, Insert, Manage, etc) and organize the Tools into common groups. Panels - Contain a group of tools Tools - These are the icon that starts the commands we use to draw, modify, etc. Tool Tip - If we however mouse over a tool, a tool tip will appear to give us more information. Hold it longer for more info. Drawing Space - These is where we draw were designs. Command line - When we type a command, we will see it here. AutoCAD uses this space to 'prompt' us for information. It will give us a lot of information and tell us where we are in the command. Status bar - This allows seeing and changing different modes of drawing such as Ortho, Osnaps, Grid, Otrack, etc. We can right click this area to toggle between icons and text for this area.
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Basic Drawing Commands for Autocad
Measuring Commands
GRID (F7): Displays a grid of dots at a desired spacing on the screen. Command: GRID (enter) On/Off/Tick spacing(x)/Aspect: (enter value) (enter)
SNAP (F9): Specifies a "round off" interval so that points entered with the mouse can be locked into alignment with the grid spacing. Command: SNAP (enter) On/Off/Value/Aspect/Rotate/Style: (enter value) (enter) Basic Draw Commands CIRCLE (C): Draws circles of any size. Command: Circle (enter) 3P/2P/TTR/
: (pick a center point) Diameter or : (Pick a point on the circle) LINE (L): Draws straight lines between two points Command: LINE (enter) From Point: (pick a point using the mouse) To Point: (Pick a point using the mouse) To Point: (Press return to end the command) ARC (A): Draws an arc (any part of a circle or curve) through three known points. Command: ARC (enter) Center/ < Start point > : (pick the first point on the arc) Center/End/ < Second point >:C Center: (pick the arc's center point) Angle/Length of chord/ : (pick the arc endpoint) Display Commands LIMITS: Sets the size of the drawing paper. For size "A" drawing paper the limits should be set for 10.5 x 8. Command: LIMITS (enter) On/Off/Lower left corner <0.0000> (enter) Upper right corner: 10.5,8 (enter)
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ZOOM (Z): Enlarges or reduces the display of a drawing. PAN: Allows we to move were view point around the drawing without changing the magnification factor. Command: PAN (enter)
Editing Commands CHANGE: Alters properties of selected objects Command: CHANGE (enter) Select objects or window or Last (select objects to be changed) Properties/: (type P) Change what property (Color/Elev/ Layer/L Type/Thickness)? (Type Layer) New Layer: (enter new layer name and press enter)
ERASE (E): Erases entities from the drawing. Command: ERASE (enter) Select objects or Window or Last: (Select objects to be erased and press enter when finished)
TRIM (TR): Trims a line to end precisely at a cutting edge. Command: Trim (enter) Select cutting edge(s)... Select Objects (pick the line which represents the cutting edge of line in which objects will be trimmed to)(press enter when finished selecting cutting edges)trim>/Undo: (pick the line(s) that need to be trimmed). Creating Layers LAYER: Creates named drawing layers and assigns color and line type properties to those layers. Command: LAYER (enter) A Layer & Line type Properties dialog box will be displayed. To add a new layer, pick the new button. A new layer listing appears, using a default name of Layer1. The layer name can be changed by highlighting the layer name. Colors and Line types can be assigned to each new layer by picking the color box to assign a color and picking the line type box to assign a line type.
Standard AutoCAD colors 1 = Red 2 = Yellow 3 = Green 4 = Cyan 5 = Blue 6 = Magenta 7 = White
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Standard AutoCAD line types Hidden2 = hidden lines Center2 = center lines Phantom2 = phantom or cutting-plane lines Construction Commands ARRAY (AR): Makes multiple copies of selected objects in a rectangular or circular pattern Command: ARRAY (enter) Select objects or Window or Last: (select object to array) Rectangular or Polar array (R/P) : (P) Center point of array: (pick the point around which to form the array) Angle to fill (+=CCW, -=Cw) <360>: (enter) COPY (CO): Draws a copy of selected objects. Command: COPY (enter) Select objects or Window or Last: (select objects to be copied) Base point or displacement: (pick a point on the object to be use as a reference point) Second point of displacement: (pick a point which represents the new location of the copied object) MIRROR(MI): Makes mirror images of existing objects. Command: MIRROR (enter) Select objects or Window or Last: (select objects to be mirrored) First point of mirror line: (pick a point on top of the mirror line) Second point: (pick a point on the bottom of the mirror line) Delete old objects? y or n (enter) MOVE(M): Moves designated entities to another location. Command: MOVE (enter) Select objects or Window or Last: (select objects to move) Base point or displacement: (pick a point on the object to be use as a reference point) Second point of displacement: (pick a point which represents the new location of the object) OFFSET (O): Constructs an entity parallel to another entity at a specified distance. Offset can be used with lines, circles, arcs, and polylines. Command: OFFSET (enter) Offset distance or Through: (enter a distance value) Select object to offset: (select object to offset) FirstRanker.com - FirstRanker's Choice
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DEPARTMENT OF MECHANICAL ENGINEERING
ME8381 ? COMPUTER AIDED MACHINE DRAWING LABORATORY III SEMESTER - R 2017
Name : _______________________________________ Register No. : _______________________________________ Section : _______________________________________
LABORATORY MANUAL
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College of Engineering is committed to provide highly disciplined, conscientious and enterprising professionals conforming to global standards through value based quality education and training.
To provide competent technical manpower capable of meeting requirements of the industry To contribute to the promotion of academic excellence in pursuit of technical education at different levels To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart and soul
DEPARTMENT OF MECHANICAL ENGINEERING
Rendering the services to the global needs of engineering industries by educating students to become professionally sound mechanical engineers of excellent caliber
To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on experience and to inculcate the spirit of moral values and ethics to serve the society
VISION MISSION VISION MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs) 1. Fundamentals To impart students with fundamental knowledge in mathematics and basic sciences that will mould them to be successful professionals 2. Core competence To provide students with sound knowledge in engineering and experimental skills to identify complex software problems in industry and to develop a practical solution for them 3. Breadth To provide relevant training and experience to bridge the gap between theory and practice which enable them to find solutions for the real time problems in industry and organization and to design products requiring interdisciplinary skills 4. Professional skills To bestow students with adequate training and provide opportunities to work as team that will build up their communication skills, individual, leadership and supportive qualities and to enable them to adapt and to work in ever changing technologies 5. Life-long learning To develop the ability of students to establish themselves as professionals in mechanical engineering and to create awareness about the need for lifelong learning and pursuing advanced degrees
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PROGRAMME OUTCOMES (POs) On completion of the B.E. (Mechanical) degree, the graduate will be able 1. To apply the basic knowledge of mathematics, science and engineering 2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the career or entrepreneurship 3. To design and develop innovative and creative software applications 4. To understand a complex real world problem and develop an efficient practical solution 5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools 6. To understand the role as a professional and give the best to the society 7. To develop a system that will meet expected needs within realistic constraints such as economical environmental, social, political, ethical, safety and sustainability 8. To communicate effectively and make others understand exactly what they are trying to tell in both verbal and written forms 9. To work in a team as a team member or a leader and make unique contributions and work with coordination 10. To engage in lifelong learning and exhibit their technical skills 11. To develop and manage projects in multidisciplinary environments
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To make the students understand and interpret drawings of machine components To prepare assembly drawings both manually and using standard CAD packages To familiarize the students with Indian standards on drawing practices and standard components To gain practical experience in handling 2D drafting and 3D modelling software systems
List of Experiments
A. Drawing standards & fits and tolerances Code of practice for Engineering drawing BIS specifications ? welding symbols, riveted joints, keys, fasteners- reference to hand book for the selection of standard components like bolts, nuts, screws, keys etc, - limits, fits- tolerancing of individual dimensions-specification of fits-preparation of production drawings and reading of part and assembly drawings, basic principles of geometric dimensioning & tolerancing
B. Introduction to 2D drafting Drawing, editing, dimensioning, layering, hatching, block, array, detailing, detailed drawing. Bearings- Bush bearing, plummer block Valves-safety and non-return valves
C. 3D Geometric modelling and assembly Sketcher-datum planes-protrusion-holes-part modelling-extrusion-revolve-sweep-loft-blend-fillet-pattern-chamfer- round-mirror-section-assembly Couplings ? Flange, Universal, Oldham?s, Muff, Gear couplings Joints ? Knuckle, Gib & cotter, strap, sleeve & cotter joints Engine parts ? piston, connecting rod, cross-head (vertical and horizontal), stuffing box, multi-plate clutch Miscellaneous machine components ? screw jack, machine vice, tail stock, chuck, vane and gear pump
Upon completion of this course, the students will be able to follow the drawing standards, fits and tolerances and re-create part drawings, sectional views and assembly drawings as per standards
COURSE OBJECTIVES
COURSE OUTCOMES
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ME8381- COMPUTER AIDED MACHINE DRAWING LABORATORY CONTENTS Sl. No. Name of the experiments Page No. 1 Study of Drawing standards and fits and tolerances 6 2 Introduction to CADD 24 3 Introduction to modeling software Pro-E 33 4 2D Drafting of Plummer block bearing 36 5 2D Drafting of Non-return valves 39 6 2D Drafting of Safety valve 42 7 3D Assembly of Flange Coupling 45 8 3D Assembly of Universal Coupling 48 9 3D Assembly of Oldham?s Coupling 51 10 3D Assembly of Knuckle joint 54 11 3D Assembly of Socket and Spigot joint 57 12 3D Assembly of Gib and Cotter joint 60 13 3D Assembly of Connecting rod 63 14 3D Assembly of Piston 66 15 3D Assembly of Stuffing box 69 16 3D Assembly of Crosshead 72 17 3D Assembly of Multi plate clutch 75 18 3D Assembly of Screw jack 79 19 3D Assembly of Machine vice 82 20 3D Assembly of Tail stock 85 21 3D Assembly of Chuck 88 22 3D Assembly of Gear pump 91 ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS 23 Introduction to LS-DYNA 94 PROJECT WORK 99
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Expt. No.01 STUDY OF DRAWING STANDARDS AND FITS AND TOLERANCES Aim: To study about the drawing standards and fits and tolerance
1.1 Code of practice for Engineering Drawing Abbrevations Term Abbreviation Term Abbreviation Across corners A/C Across flats A/F Approved APPD Approximate APPROX Assembly ASSY Auxiliary AUX Bearing BRG Centimetre Cm Centres CRS Centre line CL Centre to centre C/L Chamfered CHMED Checked CHD Cheese head CH HD Circular pitch CP Circumference OCE Continued CONTD Counterbore C BORE Countersunk CSK Cylinder CYL Diameter DIA Diametral pitch DP Dimension DIM Drawing DRG Equi-spaced EQUI-SP External EXT Maunfacture MFG Material MATL Maximum max. Metre m Mechanical MECH Millimetre mm Minimum min. Nominal NOM Not to scale NTS Number No. Opposite OPP Outside diameter OD Pitch circle PC Pitch circle diameter PCD Quantity QTY Radius R Radius in a note RAD Reference REF Required REQD Right hand RH Round RD Screw SCR Serial number Sl. No. Specification SPEC Sphere/Spherical SPHERE Spot face SF
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Figure FIG. General GNL Ground level GL Ground GND Hexagonal HEX Inspection INSP Inside diameter ID Internal INT Left hand LH Machine M/C
Square SQ Standard STD Symmetrical SYM Thick THK Thread THD Through THRU Tolerance TOL Typical TYP Undercut U/C Weight WT
Standard Codes
Sl.No. IS-CODE DESCRIPTION 1 IS:9609-1983 Lettering on Technical Drawing 2 IS:10711-1983 Size of drawing sheets 3 IS:10713-1983 Scales for use on technical drawing 4 IS:10714-1983 General Principles of Presentation 5 IS:10715-1983 Presentation of threaded parts on technical drawing 6 IS:10716-1983 Rules for presentation of springs 7 IS:10717-1983 Conventional representation of gears on technical drawing 8 IS:11663-1986 Conventional representation of common features 9 IS:11664-1986 Folding of drawing prints 10 IS:11665-1986 Technical drawing ? Title blocks 11 IS:11669-1986 General principles of dimension on technical drawing 12 IS:11670-1986 Abbreviations for use in Technical Drawing
1.2 Welding symbols Welding is a process of fastening the metal parts together permanently by the application of heat (fusion welds) or pressure (pressure or forge welding) or both (resistance welding). Both ferrous (steel, cast iron) and Non-ferrous metals (like brass copper and alloy) can be joined by welding.
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The various types of welding process are a. Gas welding b. Arc welding Metal Arc Welding (MAW) Gas metal Arc Welding (GMAW) Submerged Arc Welding (SAW) Tungsten Inert Gas Welding (TIG) Metal Inert Gas Welding (MIG) c. Forge Welding d. Resistance Welding e. Thermit Welding f. High Energy Welding
A welding symbol may include the following elements:
1. Reference line 2. Arrow line 3. Basic weld symbol 4. Dimensions & other data 5. Supplementary symbols 6. Finish symbols 7. Tail 8. Specifications, process, or other references
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The position of the arrow line with respect to the weld is of no special significance. The side of the joint on which the arrow line is drawn is called ?arrow side?. The side of the joint remote to the arrow line is called ?other side?. The reference line has significance on the weld side. If the weld symbol is placed BELOW the reference line, the welding should be done in the ?ARROW SIDE?. If the weld symbol is placed ABOVE the reference line, the welding should be done in the ?OTHER SIDE?. If the weld symbol is placed both ABOVE and BELOW the reference line, the welding should be done in both the ?ARROW and OTHER SIDES?. Basic Weld Symbol The basic symbols recommended by Bureau of Indian Standards (BIS) for specifies the type of weld are shown in the fig.
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1.3 Riveted Joints A riveted joint is a permanent type of fastener used to join the metal plates or rolled steel sections together. Riveted joints are extensively used in structural works such as bridges and roof trusses and in the construction of pressure vessels such as storage tanks, boilers, etc. Although welded joints are best suited to several of these applications than the riveted joints, however, riveted joints are ideal in cases where the joints will be subjected to pronounced vibrating loads. Riveted joints are also used when a non-metallic plate and a metallic plate are to be connected together. They are also used when the joints are not expected to be heated while joining as in welding, which may cause warping and tempering of the finished surfaces of the joints. The disadvantage of riveted joints are: (i) more metal is removed while making of the holes, which weakens the working cross sections along the line of the rivet holes, and (ii) weight of the rivets increases the weight of the riveted members. A rivet is a round rod made either from mild steel or non-ferrous materials such as, copper, aluminium, etc., with a head is, and formed at one end during its manufacture and its tail end being slightly tapered. The length of the shank of the rivet must be sufficient enough to accommodate the connection plates and provide enough material for forming a head at its shank end. In general, the shank of the rivet will be equal to sum of the thickness of the connecting plates plus 1.5 to 1.7 times the diameter of the rivet. If, ?? = length of the shank of the rivet d = diameter of rivet t = thickness of each of the connecting plates then, ?? = ???? + (1.5 ???? 1.7)??
Various types of rivet heads for the use in general engineering work and boiler work as recommended by the Bureau of Indian Standards. The different proportions of these rivet heads are given in terms of the nominal diameter d of the rivet. The rivet head to be used for general purposes for diameter below 12 mm are specified in the Indian Standard code IS:2155-1962 and for diameters between 12 and 48 mm are specified in the Indian Standard code IS:1929-1961. The rivet heads to be used for boiler work are specified in the Indian Standard code IS: 1928-1961. The rivet heads to be used for ship building are specified in the Indian Standard code IS: 4732- 1968.
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Types of rivet heads
1.4 Screw Threads, Keys and Fasteners Screw Threads A screw thread is a functional element used on bolt, stud, set screw, nut or any other threaded piece or component. Screw thread is a helical groove on a cylinder surface (outer side or inner side). Its function is to transform the input motion of rotation into output motion of translation. If a cylindrical rod is rotated at a constant speed simultaneously if a pointed tool touching the rod moving parallel to the axis of the rod at constant speed, the cut made by tool on the rod will be continuous and of helical form. The helical groove is called ?thread? and the threaded rod is called a ?screw?. Threads are cut using a lathe. Small size thread is often cut by means of a tool called die. A small size hole is threaded by means of a tool called a tap. The principal uses of threads are, 1. for fastening 2. for adjusting 3. for transmitting power
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Terms and Nomenclature
1. Crest: It is the peak edge of a screw thread that connects the adjacent flanks at the top. 2. Root: It is the bottom edge of the thread that connects the adjacent flanks at the bottom. 3. Flank or side: It is the straight portion of the surface, on either side of the screw thread. 4. Angle of the thread: It is the angle included between the sides of two adjacent threads measured on an axial plane. 5. Depth of the thread: It is the distance between the crest and the root measured at Right angle to the axis. It is equal to half the difference between the outer diameter and the core diameter. 6. Major diameter or outside diameter: It is the diameter of the imaginary coaxial cylinder, which would bind the crests of an external or internal thread. 7. Minor or core or root diameter: It is the diameter of the imaginary coaxial cylinder; this would bind the roots of an external thread or of an internal thread. 8. Pitch diameter: It is the diameter of the imaginary coaxial cylinder that can be passed so as to cut the thread, that the width of the cut thread will be equal to the Width of the groove. 9. Pitch: It is the axial distance between a point on one thread and the corresponding Point on the next thread. It may be indicated as the distance from crest or from root of two adjacent threads. 10. Lead: It is the distance measured parallel to the axis from a point on a thread to the corresponding point on the same thread for one complete revolution. In other words, it is axial distance a screw advances in one revolution. 11. External thread: It is the thread on the outside surface of a member such as bolt, studs or screw. 12. Internal thread: It is the thread on the inside surface of a member such as nut or threaded hole. 13. Right hand thread: Right hand thread if turned clockwise direction advances into a threaded hole. It abbreviated as RH. 14. Left hand thread: Left hand thread if turned anticlockwise direction advances into a threaded hole. It abbreviated as LH.
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V- THREADS British standard whit worth thread (BSW) This thread was introduced by Sir Joseph whit worth, and was standardized as British standard thread. It has a thread angle of 55 degree and is rounded equally at crest and roots. British Association threads (B.A Threads) The angle between flanks is 47.5 degree. These threads are to supplement BSW and have fine pitches. They are used on screws for precision work. American standard threads (or) sellers thread The thread angle is 60 degree and both the crests and roots are kept flat. The sellers thread has been in use in USA and Canada. Unified screw threads The countries UK, U.S.A and Canada came to an arrangement for a common screw thread system with the included angle of 60 degree and designated as unified screw thread in the year 1949. The thread on the bolt is rounded off at the crest and root and the thread in the nut is rounded off at the root but the crest is left flat. This thread is very important in the motor and aeroplane industries and in chemical engineering. Unified thread can be either coarse (UNC) or fine (UNF) and unified national extra fine (UEF). ISO Metric Thread This is Indian standard thread for ISO (International Standard Organization). The included angle is 60 0 and the crests are flat and roots are round. Metric threads are grouped into diameter pitch combination differentiated by the pitch applied to specific diameters. There are coarse, constant, fine pitch series available. ISO metric threads are defined by nominal size (Basic major diameter) and pitch both expressed in millimeters. for example, a 10mm diameter, 1.25 pitches is expressed as M10?1.25. SQUARE THREADS Basic square thread The sides of these threads are normal to the axis and parallel to each other. The depth and the thickness of the thread are equal to half pitch. A square thread is designated by the letter SQ followed by nominal diameter pitch. For example a square thread of nominal diameter 30mm and pitch 6mm is designated as SQ 30?6. Acme Thread It is a modified form of square thread. It is easier to cut and is much stronger than square thread. It has a 29 0
thread angle. This inclined sides of the thread facilitate quick and early engagement and disengagement. It is used for power screws like lead screw of lathe, jackscrews, bench vices and valve operating screws.
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Buttress Thread The profile of this thread is a combination of square and V- threads. It combines the low frictional of square and ability to transmit power of square thread and the strength of V ? thread. It is used to transmit load in uni-direction. These threads are used in screw press, vices.
Knuckle Thread It is also a modification of square thread. The sharp corners of square thread are rounded off. This thread is used where heavy wear rough use is expected. The thread can be rolled or cast easily. It is used in railway carriage coupling screws, light bulbs and sockets, bottle caps etc and also objects made of brittle materials as glass, plastic, porcelains etc.
Types of thread profiles
Keys Keys are machine elements used to prevent relative rotational movement between a shaft and the parts mounted on it, such as pulleys, gears, wheels, couplings, etc. for making the joint, keyways are cut on the surface of the shaft and in the hub of the part to be mounted. After positioning the part on the shaft such that, both the keyways are properly aligned, the key is driven from the end, resulting in a firm joint. For mounting a part at any intermediate location on the shaft, first the key is firmly placed in the keyways of the shaft and then the part to be mounted is slid from one end of the shaft, till it is fully engaged with the key. Keys are classified into three types. 1. Saddle keys I. flat saddle key II. hollow saddle key
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2. Sunk keys I. taper sunk keys II. parallel sunk keys III. woodruff keys 3. Round keys
Types of keys
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Bolt and nuts A bolt and nut in combination is a fastening device used to hold two parts together. The body of the bolt, called shank is cylindrical in form, the head; square or hexagonal in shape, is formed by forging. Screw threads are cut on the other end of the shank. Nuts in general are square or hexagonal in shape. The nuts with internal threads engage with the corresponding size of the external threads of the bolt. However, there are other forms of nuts used to suit specific requirements. For nuts, hexagonal shape is preferred to the square one, as it is easy to tighten even in a limited space. This is because, with only one-sixth of a turn, the spanner can be reintroduced in the same position. However, square nuts are used when frequent loosening and tightening is required. The sharp corners on the head of bolts and nuts are removed by chamfering. Empirical portions of hexagonal and square head bolt & nut detail proportion Nominal diameter d = size of bolt or nut, mm Width across flats s = 1.5d+3 mm Width across corners e = 2d Thickness of bolt head k = 0.8d Thickness of nut, n = 0.9d Root diameter, d1 = d - (2 ? depth of thread) Length of the bolt L = as specified Thread length b = 2d+6mm (for l<150mm) = 2d+12mm (for l>150mm) Chamfer of bolt end, Z = (depth of thread ? 45 0 ) or =0.1d Chamfer angle of bolt head & nut 30 0
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1.5 Limits, fits and tolerances Limit System Following are some of the terms used in the limit system: Tolerance: The permissible variation of a size is called tolerance. It is the difference between the maximum and minimum permissible limits of the given size. If the variation is provided on one side of the basic size, it is termed as unilateral tolerance. Similarly, if the variation is provided on both sides of the basic size, it is known as bilateral tolerance. Limits: The two extreme permissible sizes between which the actual size is contained are called limits. The maximum size is called the upper limit and the minimum size is called the lower limit. Deviation: It is the algebraic difference between a size (actual, maximum, etc.) and the corresponding basic size. Actual deviation: It is the algebraic difference between the actual size and the corresponding basic size. Upper deviation: It is the algebraic difference between the maximum limit of the size and the corresponding basic size. Lower deviation: It is the algebraic difference between the minimum limit of the size and the corresponding basic size. Allowance: It is the dimensional difference between the maximum material limits of the mating parts, intentionally provided to obtain the desired class of fit. If the allowance is positive, it will result in minimum clearance between the mating parts and if the allowance is negative, it will result in maximum interference. Basic Size: It is determined solely from design calculations. If the strength and stiffness requirements need a 50mm diameter shaft, then 50mm is the basic shaft size. If it has to fit into a hole, then 50 mm is the basic size of the hole. Here, the two limit dimensions of the shaft are deviating in the negative direction with respect to the basic size and those of the hole in the positive direction. The line corresponding to the basic size is called the zero line or line of zero deviation.
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Fits The relation between two mating parts is known as a fit. Depending upon the actual limits of the hole or shaft sizes, fits may be classified as clearance fit, transition fit and interference fit.
Clearance Fit: It is a fit that gives a clearance between the two mating parts. minimum clearance: It is the difference between the minimum size of the hole and the maximum size of the shaft in a clearance fit. maximum clearance: It is the difference between the maximum size of the hole and the minimum size of the shaft in a clearance or transition fit. The fit between the shaft and hole in Fig. is a clearance fit that permits a minimum clearance (allowance) value of 29.95 ? 29.90 = + 0.05 mm and a maximum clearance of + 0.15 mm.
Transition Fit: This fit may result in either interference or a clearance, depending upon the actual values of the tolerance of individual parts. The shaft in Fig. may be either smaller or larger than the hole and still be within the prescribed tolerances. It results in a clearance fit, when shaft diameter is 29.95 and hole diameter is 30.05 (+ 0.10 mm) and interference fit, when shaft diameter is 30.00 and hole diameter 29.95 (? 0.05 mm).
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Interference fit: If the difference between the hole and shaft sizes is negative before assembly; an interference fit is obtained. minimum interference: It is the magnitude of the difference (negative) between the maximum size of the hole and the minimum size of the shaft in an interference fit before assembly. maximum interference: It is the magnitude of the difference between the minimum size of the hole and the maximum size of the shaft in an interference or a transition fit before assembly. The shaft in fig. is larger than the hole, so it requires a press fit, which has an effect similar to welding of two parts. The value of minimum interference is 30.25 ? 30.30 = ? 0.05 mm and maximum interference is 30.15 ? 30.40 = ? 0.25 mm.
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Schematic representation of fits:
Tolerance It is impossible to make anything to an exact size, therefore it is essential to allow a definite tolerance or permissible variation on every specified dimension. Tolerances are specified because ? Variations in properties of the material being machined introduce errors. ? The production machines themselves may have some inherent inaccuracies. ? It is impossible for an operator to make perfect settings. While setting up the tools and workpiece on the machine, some errors are likely to creep in.
Form variation: It is a variation of the actual condition of a form feature (surface, line) from geometrically ideal form. Position variation: It is a variation of the actual position of the form feature from the geometrically ideal position, with reference to another form (datum) feature. Geometrical tolerance: Geometrical tolerance is defined as the maximum permissible overall variation of form or position of a feature.
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Geometrical tolerances are used, (i) to specify the required accuracy in controlling the form of a feature, (ii) to ensure correct functional positioning of the feature, (iii) to ensure the interchangeability of components, and (iv) to facilitate the assembly of mating components. Tolerance zone: It is an imaginary area or volume within which the controlled feature of the manufactured component must be completely contained Datum: It is a theoretically exact geometric reference (such as axes, planes, straight lines, etc.) to which the tolerance features are related. Datum feature: A datum feature is a feature of a part, such as an edge, surface, or a hole, which forms the basis for a datum or is used to establish its location
Datum triangle: The datums are indicated by a leader line, terminating in a filled or an open triangle. Datum letter: To identify a datum for reference purposes, a capital letter is enclosed in a frame, connected to the datum triangle.
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Expt. No.02 INTRODUCTION TO CADD CADD is an electronic tool that enables us to make quick and accurate drawings. CADD has number of advantages over drawings created on a drawing board. Electronic drawings can be modified quite easily and can be represented in a variety of formats. CADD extends its power to yet another branch of engineering called computer aided manufacturing (CAM).CADD and manufacturing program are often integrated into one system called CAD-CAM. This system import CADD drawings into CAM program to automate the manufacturing process. When the design is finalized, the drawings are brought into a CAD-CAM system that uses numerical data from the CADD drawing for actual manufacturing. There is separate category of programs called Computer Aided Engineering (CAE) that can use CADD drawing for engineering analysis. The CAE programs have a number of applications in Structural Design, Civil Engineering, Mechanical Engineering and Electrical Engineering. The Mechanical engineer can test a machine assembly and also a prototype electronic model and test it without building a physical model. We can do amazing things with CADD that we never thought possible while creating drawings with pen or pencil. The following are some of the important capabilities that make CADD a powerful tool. ? Presentations ? Flexibility in editing ? Unit and accuracy levels ? Storage and access for drawings ? Sharing CADD drawings Presentations There are a number of ready-made presentations symbols available in CADD that can be used to enhance the look of drawings. In addition to prepare impressive presentations on paper, we can use CADD to make an on-screen presentations. Advanced CADD programs ever allow us to create an animated image. Flexibility in editing CADD allows us to work with great accuracy. If we need to create highly accuracy geometric shapes, CADD is the answer. It can help avoid time-consuming mathematical calculations. Unit and accuracy level We can work with as high precession as 1/1000 th of an inch. Storage and access of drawing A computer electronic filing system has the following advantages over the traditional filing system.
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? It is quick and convenient to organize CADD drawing in a computer. ? It enables us to create a highly organized environment. ? An electronic drawing never gets old and faded. Sharing CADD Drawing The electronic drawing can be shared by a number of users, allowing them to Co-ordinate projects and work as a team. This is accomplished by connecting different computer via a network.
About AutoCAD
AutoCAD is a Computer Aided Design (CAD) program used by just about every Engineering and Design office in the world. Although there are alternative CAD packages, AutoCAD is by far the most widely used system. Autodesk's AutoCAD is the industry leader in CAD packages. Used by Civil Engineers, Architects, Mechanical and Electrical Engineers, Aeronautical Engineers plus many other disciplines. There have been several versions of AutoCAD over the years, with each new version introducing new and more powerful features than its predecessor. The latest version of AutoCAD (at the time of writing) is AutoCAD 2011. Any courses, whether through community colleges or online universities, that are related to Engineering or Architecture should be considered incomplete if they do not introduce students to AutoCAD. Accurate, scale drawings can be created and published using AutoCAD powerful features. 3D 'models' can also be created giving the designer absolute control over the design from start to finish. The computerized model can be viewed through a 360? angle, and even 'rendered' with a texture on screen to give an idea of the finished product. Co-ordinate system
AutoCAD uses points to determine where an object is located. There is an origin where it begins counting from. This point is (0,0). Every object is located in relation to the origin. If we were to draw a line straight out to the right from
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the origin, this would be considered the positive X-axis. If we were to draw a line straight up, this would be the positive Y-axis. The picture above shows a point located at (9, 6). This means that the point is 9 units over in the X- axis and 6 units up in the Y-axis. When we are working with points, X always comes first. The other point shown is (-10,-4). This means that the point is 10 units in the negative X-axis (left) and 4 units in the negative Y-axis (down).
A line has two points, a start point and an end point. AutoCAD works with the points to display the line on the screen. Most of the time we will not have an indication of where the origin is. We may need to draw a line from the endpoint of an existing line. To do this we use relative points. These work the same way, but we have to add the @ symbol (shift+2) to tell AutoCAD that this next point is relative from the last point entered. i.e. 1. ABSOLUTE POINTS are exact points on the drawing space. 2. RELATIVE POINTS are relative to an OBJECT on the drawing space Angular Measurement AutoCAD measures angles in a particular way also.
When drawing lines at an angle, we have to begin measuring the angle from 0 degrees, which is at the 3 o'clock position. If we drew a line at 90 degrees, it would go straight up. The example shows a line drawn at +300 degrees (270+30), or -60 degrees.
Entering Points in AutoCAD We can enter points directly on the command line using three different systems. The one we use will depend on which is more applicable for the situation. The three systems are as follows:
ABSOLUTE CO-ORDINATES - Using this method, we enter the points as they relate to the origin of the WCS. To enter a point just enters in the exact point as X, Y.
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RELATIVE CO-ORDINATES - This allows us to enter points in relation to the first point we have entered. After we've entered one point, the next would be entered as @X, Y. This means that AutoCAD will draw a line from the first point to another point X units over and Y units up relative to the previous point. POLAR CO-ORDINATES - We would use this system if we know that we want to draw a line a certain distance at a particular angle. We would enter this as @D@10<90 will draw a line 10 units straight up from the first point. The three ways of entering co-ordinates shown above are the ONLY way AutoCAD accepts input. First decide which style we need to use, and then enter as shown. Remember that X is always before Y (alphabetical). Don't forget the '@' symbol when we are entering relative points. AutoCAD Basics Application Button - This button displays commands for printing, saving, drawing utilities and other non-drawing tool. Quick Access Toolbar - This is for quick access to common commands like New, Open, Save, Plot Filename - The name of the current file we are working on. Search Bar - Search for text in were drawing or search the help files. Ribbon - The Ribbon has most of the commands/tools that we will use while we are working. Tabs - A series of Tabs make up the Ribbon (Home, Insert, Manage, etc) and organize the Tools into common groups. Panels - Contain a group of tools Tools - These are the icon that starts the commands we use to draw, modify, etc. Tool Tip - If we however mouse over a tool, a tool tip will appear to give us more information. Hold it longer for more info. Drawing Space - These is where we draw were designs. Command line - When we type a command, we will see it here. AutoCAD uses this space to 'prompt' us for information. It will give us a lot of information and tell us where we are in the command. Status bar - This allows seeing and changing different modes of drawing such as Ortho, Osnaps, Grid, Otrack, etc. We can right click this area to toggle between icons and text for this area.
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Basic Drawing Commands for Autocad
Measuring Commands
GRID (F7): Displays a grid of dots at a desired spacing on the screen. Command: GRID (enter) On/Off/Tick spacing(x)/Aspect: (enter value) (enter)
SNAP (F9): Specifies a "round off" interval so that points entered with the mouse can be locked into alignment with the grid spacing. Command: SNAP (enter) On/Off/Value/Aspect/Rotate/Style: (enter value) (enter) Basic Draw Commands CIRCLE (C): Draws circles of any size. Command: Circle (enter) 3P/2P/TTR/
: (pick a center point) Diameter or : (Pick a point on the circle) LINE (L): Draws straight lines between two points Command: LINE (enter) From Point: (pick a point using the mouse) To Point: (Pick a point using the mouse) To Point: (Press return to end the command) ARC (A): Draws an arc (any part of a circle or curve) through three known points. Command: ARC (enter) Center/ < Start point > : (pick the first point on the arc) Center/End/ < Second point >:C Center: (pick the arc's center point) Angle/Length of chord/ : (pick the arc endpoint) Display Commands LIMITS: Sets the size of the drawing paper. For size "A" drawing paper the limits should be set for 10.5 x 8. Command: LIMITS (enter) On/Off/Lower left corner <0.0000> (enter) Upper right corner: 10.5,8 (enter)
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ZOOM (Z): Enlarges or reduces the display of a drawing. PAN: Allows we to move were view point around the drawing without changing the magnification factor. Command: PAN (enter)
Editing Commands CHANGE: Alters properties of selected objects Command: CHANGE (enter) Select objects or window or Last (select objects to be changed) Properties/: (type P) Change what property (Color/Elev/ Layer/L Type/Thickness)? (Type Layer) New Layer: (enter new layer name and press enter)
ERASE (E): Erases entities from the drawing. Command: ERASE (enter) Select objects or Window or Last: (Select objects to be erased and press enter when finished)
TRIM (TR): Trims a line to end precisely at a cutting edge. Command: Trim (enter) Select cutting edge(s)... Select Objects (pick the line which represents the cutting edge of line in which objects will be trimmed to)(press enter when finished selecting cutting edges)trim>/Undo: (pick the line(s) that need to be trimmed). Creating Layers LAYER: Creates named drawing layers and assigns color and line type properties to those layers. Command: LAYER (enter) A Layer & Line type Properties dialog box will be displayed. To add a new layer, pick the new button. A new layer listing appears, using a default name of Layer1. The layer name can be changed by highlighting the layer name. Colors and Line types can be assigned to each new layer by picking the color box to assign a color and picking the line type box to assign a line type.
Standard AutoCAD colors 1 = Red 2 = Yellow 3 = Green 4 = Cyan 5 = Blue 6 = Magenta 7 = White
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Standard AutoCAD line types Hidden2 = hidden lines Center2 = center lines Phantom2 = phantom or cutting-plane lines Construction Commands ARRAY (AR): Makes multiple copies of selected objects in a rectangular or circular pattern Command: ARRAY (enter) Select objects or Window or Last: (select object to array) Rectangular or Polar array (R/P) : (P) Center point of array: (pick the point around which to form the array) Angle to fill (+=CCW, -=Cw) <360>: (enter) COPY (CO): Draws a copy of selected objects. Command: COPY (enter) Select objects or Window or Last: (select objects to be copied) Base point or displacement: (pick a point on the object to be use as a reference point) Second point of displacement: (pick a point which represents the new location of the copied object) MIRROR(MI): Makes mirror images of existing objects. Command: MIRROR (enter) Select objects or Window or Last: (select objects to be mirrored) First point of mirror line: (pick a point on top of the mirror line) Second point: (pick a point on the bottom of the mirror line) Delete old objects? y or n (enter) MOVE(M): Moves designated entities to another location. Command: MOVE (enter) Select objects or Window or Last: (select objects to move) Base point or displacement: (pick a point on the object to be use as a reference point) Second point of displacement: (pick a point which represents the new location of the object) OFFSET (O): Constructs an entity parallel to another entity at a specified distance. Offset can be used with lines, circles, arcs, and polylines. Command: OFFSET (enter) Offset distance or Through: (enter a distance value) Select object to offset: (select object to offset)
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Side to offset: (Pick any point on the side of the object we wish to offset) FILLET (FI): Changes any corner to a rounded corner. Command: FILLET Polyline/Radius/Angle/Trim/Method/