2012_june[1]

CONFIDENTIAL EM/JUN2012/MEM560

UNIVERSITI TEKNOLOGI MARA FINAL EXAMINATION

COURSE

COURSE CODE

EXAMINATION

TIME

MANUFACTURING PROCESSES

MEM560

JUNE 2012

3 HOURS

INSTRUCTIONS TO CANDIDATES

1. This question paper consists of seven (7) questions.

Answer six (6) questions in the Answer Booklet. Start each answer on a new page. 2.

3.

4.

Do not bring any material into the examination room unless permission is given by the invigilator.

Please check to make sure that this examination pack consists of:

i) the Question Paper ii) an Answer Booklet - provided by the Faculty

DO NOT TURN THIS PAGE UNTIL YOU ARE TOLD TO DO SO

This examination paper consists of 5 printed pages

© Hak Cipta Universiti Teknologi MARA CONFIDENTIAL

CONFIDENTIAL 2 EM/JUN2012/MEM560

QUESTION 1

a) Unit production and mass are production methods normally used by manufacturers. Compare and distinguish between these two methods in term of characteristics, advantages and disadvantages.

(4 marks)

b) What is metrology and give at least four (4) reasons why engineering metrology is so important in engineering practices?

(3 marks)

c) All the terminologies listed below are related to Metrology and Instrumentation. Briefly explain the meaning of these terminologies given below:

i) Inch-pound system

ii) ISO

iii) SI units

iv) Micrometer

v) Strain gauge

vi) Protractor

(3 marks)

QUESTION 2

a) Metal forming processes are carried out at various temperatures. What are the advantages and disadvantages of hot working over cold working of metals?

(2 marks)

b) Describe briefly the required properties of an extrusion die and explain why those properties are required for an extrusion process.

(2 marks)

c) If the force required for piercing process in sheet metal working is 30 kN, calculate the minimum press capacity required to carry out the job effectively.

(3 marks)

d) Cup drawing is a cold working metal forming process to form a round or flat-shaped blank into a desired form. For a cup drawing process, derive a formula for calculating the blank diameter D, for a simple cup-shaped product of diameter d and depth h, assuming a negligible radius in the bottom corner.

(3 marks)



QUESTION 3

Casting is a process where molten metal flows into a mould and solidifies in the shape of the mould cavity.

a) Identify four (4) important factors affecting the selection of a casting process. (2 marks)

b) Investment casting is an old casting technique where an expendable mould is coated with a refractory material to form the casting mould.

i) Describe the characteristics of the products produced from investment casting. (2 marks)

ii) Specify the advantages and disadvantages of the precision investment casting process over other casting processes.

(4 marks)

c) A variety of defects may result in cast parts due to many reasons. Briefly explain four (4) common casting defects in the cast parts.

(2 marks)

QUESTION 4

a) Compare the differences between brazing and soldering? (2 marks)

b) Briefly describe Resistance Spot Welding (RSW) process and give three (3) main limitations of this process.

(4 marks)

c) Arc welding is a metallurgical fusion process where heat is generated by electric arc to weld metallic pieces. Using suitable diagram, explain the basic mechanism of arc welding process.

(4 marks)


CONFIDENTIAL 4 EM/JUN 2012/MEM560

QUESTION 5

a) In metal cutting, continuous chip with built-up-edge affects the dimensional accuracy, surface finish of the product and decreasing the cutting tool life. How these unwanted problems in metal cutting can be improved.

(3 marks)

b) Discuss at least three (3) qualities of a cutting tool material that the machinist should select in order to machine a cylindrical high carbon steel effectively.

(3 marks)

c) Cutting tool geometry is an important element in tool selection in metal cutting and the rake angle is one of the angles in tool geometry.

i) What are the advantages and disadvantages of negative rake angle?

ii) What are the advantages and disadvantages of positive rake angle?

(4 marks)

QUESTION 6

a) Give a suitable Non-Traditional Machining (NTM) process to machine each of the following components or materials:

i)

ii)

iii)

iv)

v)

vi)

Glass

Ceramic

Cast iron

HSS

Turbine blade

Wire drawing die

(3 marks)

b) Eieptrical Discharge Machining (EDM) is a machining process where materials are removed by series of electrical discharges (or sparks).

i) Give two (2) suitable dielectric fluids for EDM process? (1 mark)

ii) Determine two (2) functions of dielectric fluid. (2 marks)



iii) EDM can be classified into two main categories: EDM die sinking and EDM wire cutting. With the help of schematic diagram, explain the main differences of the two (2) machining processes in terms of machining principle and product produced.

(4 marks)

QUESTION 7

a) Injection moulding process is a widely applied for plastic processing. Describe the reasons why the process is popular in plastic industries.

(2 marks)

b) Describe at least two (2) common defects and their causes in plastic production using plastic injection moulding process.

(2 marks)

c) Powder metallurgy (P/M) applications enable the manufacturing of small, intricate parts of high precision resulting in high density, net-shape and the elimination of scrap during the process. Discuss the importance of each of the following processes:

i) Mixing and blending

ii) Compacting

iii) Isostatic compression

iv) Sintering

(6 marks)

END OF QUESTION PAPER


2012_june[1]

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