GUJARAT TECHNOLOGICAL UNIVERSITY
SEMESTER-IV(NEW) - EXAMINATION - SUMMER 2019
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Subject Code:2142301 Date:09/05/2019
Subject Name: Basic Plastic Processing and Thermal Engineering
Time:02:30 PM TO 05:00 PM Total Marks: 70
Instructions:
- Attempt all questions.
- Make suitable assumptions wherever necessary.
- Figures to the right indicate full marks.
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MARKS
Q.1 (a) What is Plastic Processing? List various processing methods for thermoplastics and thermosets. 03
(b) What are Bulk factor and Preforms? Give Advantages and limitations of Preforms. 04
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(c) With neat diagram explain Rotational molding process steps. 07
Q.2 (a) Define: Thermoforming. List various thermoforming processes. Give any two applications of thermoforming products. 03
(b) Define: Mold, Cavity, Blow ratio, Vent. 04
(c) Explain with neat diagram (i) Drape forming (ii) Twin sheet thermoforming. 07
OR
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(c) With neat diagram explain Plunger type transfer molding process. 07
Q.3 (a) Give difference between Extrusion Blow molding and Injection Blow molding. 03
(b) Which are the factors to be considered for Compression molding? Discuss. 04
(c) Give advantages and limitations and applications of Rotational molding. 07
OR
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Q.3 (a) The outer surface of a 0.3m-thick concrete wall (10mx3m) is kept at a temperature of 10 °C while the inner surface is kept at 40 °C. Thermal conductivity of the concrete is 1.2 W/mK. Determine the rate of heat loss through it. 03
(b) Give causes and remedies in Blow molding process for following defects: (i) Parison Curl (ii) Rough Parison (iii) Warpage (iv) Variable wall thickness. 04
(c) Give principle of Stretch Blow molding and explain Injection blow molding process with neat diagram. 07
Q.4 (a) The outer surface temperature of a roof is 40 °C and that of the ambient air is 10 °C. Calculate the rate of heat exchange between ambient air and 250 m² of outer roof area if the value of convective heat transfer coefficient is 10 W/ m²K. 03
(b) Discuss melt stability and plastic memory properties for material selection criteria in thermoforming. 04
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(c) What is the role of Heat Exchanger? Discuss various types of Heat exchanger in detail. 07
OR
Q.4 (a) What is the purpose of Preheating? List various method used for the same. 03
(b) What are the different types of materials used for rotational mold? Discuss in brief. 04
(c) Write a note on: Parison Programming 07
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Q.5 (a) Differentiate between Blow molding & Injection molding process. 03
(b) What is Pinch off? Explain materials used for preparation of Blow Mold. 04
(c) What is conduction? Give heat conduction equation using Fourier’s Law. 07
OR
Q.5 (a) Give advantages and disadvantages of Transfer molding. 03
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(b) List types of compression molds and explain any one with diagram. 04
(c) Explain Plug assist thermoforming process with neat diagram. 07
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