GUJARAT TECHNOLOGICAL UNIVERSITY
BE SEM-V Examination-Nov/Dec.-2011
Subject code: 151901
Subject Name: Manufacturing Processes-II
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) What is pattern? List different types of patterns and explain
any two with neat sketch.
(b) Explain the following:
(i) Rapping allowances
(ii) Distortion allowances
Q.2 (a) List factors which affect salvaging of casting. Also list
various salvage techniques of casting and explain any one.
(b) Discuss: (i) Shell Moulding (ii) Die Casting
(b) Explain the properties of moulding sand.
Q.3 (a) What determines whether a certain welding process can be
used for workpiece in a horizontal, vertical, or an upsidedown
position, or for all types of positions? Explain, giving
(b) Two flat copper sheets of 1.2mm thickness each are spot
welded. The process parameters are: current = 5000A,
Current flow time = 0.20second, and diameter of electrodes
= 6mm. Estimate the heat generated in the welding zone.
Q.3 (a) Explain the factors involved in electrode selection in arc
(b) A steel tube of 76mm outer diameter and 4mm thickness is
welded to a flat piece by applying friction welding process
with the following information: Energy applied E=IS2/C,
where I= Moment of inertia of the flywheel, S = spindle
speed in rpm, C = proportionality constant = 250, weld
zone = 5mm deep, and energy required to melt the
electrode = 0.14kg-m. If the entire energy of the flywheel is
used to heat the electrode, what is the required moment of
inertia of the flywheel?.
Q.4 (a) Explain why there might be a change in density of a forged
product as compared to that of the cast blank.
(b) Explain how you would go about applying front and back tensions to sheet metals during rolling
Q.4 (a) It was stated that the extrusion ratio, die geometry,
extrusion speed, and billet temperature all affect the
extrusion pressure. Explain why.
Q.4 (b) How would you go about preventing center burst defects in
extrusion? Explain why your methods would be effective.
Q.5 (a) With the aid of sketches, compare the principles of
compression moulding, injection moulding and extrusion
moulding. Describe where each would be used in terms of materials and components.
(b) Explain with sketch and application: Cylindrical and
Center less grinding process for finishing operation.
Q.5 (a) Explain what is meant by term Inserts, and explain where
they are of use in plastic moulding. Sketch a typical
component showing the position of the Inserts and explain
(b) Explain: (i) Barrel Tumbling (ii) Polishing operation