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Sample Question Paper for 9210-132
Graduate Diploma in Mechanical Engineering
Manufacturing technology
Duration: three hours
You should have the
following for this examination
• one answer book
• non-programmable calculator
• pen, pencil, drawing
instruments
General instructions
• This paper consists of eight questions.
• Answer any five questions.
• A non-programmable electronic calculator may be used but candidates must show
sufficient steps to justify their answers.
• Drawings should be clear, in good proportion and in pencil. Do not use red ink.
• All questions carry equal marks. The maximum marks for each section within a
question are shown.
1
a)
b)
c)
Metal forming processes are broadly classified into hot and cold working on metals.
i)
Distinguish between hot and cold working on metals in the context of
forming processes.
ii) List two examples each for hot and cold working processes.
In the context of metal deformation processes, formulate the relationship between;
i)
engineering strain and true strain
ii) engineering stress and true stress.
A certain steel undergoing a forming process is governed by the strain hardening
equation
(2 marks)
(4 marks)
(3 marks)
(3 marks)
σ = 1200 ε0.5 MN/m2
where σ and ε are the true stress and true strain respectively.
Determine the true ultimate tensile stress and the engineering ultimate tensile
stress of this metal.
2
a)
b)
c)
d)
3
a)
b)
c)
Why are casting processes most often selected over other manufacturing
processes? Give at least four reasons.
State four design considerations that have to be taken into account in order to
avoid defects in castings.
The size and the placement of risers play a major role in the designing of
expandable-mould castings.
i)
Explain the purpose of risers.
ii) List four basic rules that need to be complied with when designing risers.
Consider the following two manufacturing scenarios of producing products
using casting processes. For each scenario, recommend suitable casting
process/processes and justify your selection.
i)
Large casting with complex design having several cores.
ii) Intricate casting with thin walls.
In metal cutting operations (machining) various types of chips are generated.
i)
What are the main three types of chips generated during cutting operations?
ii) What are conditions under which the above three types of chips are formed?
Name at least two conditions for each of the three different types of chips.
Using the idealised chip formation model for an orthogonal cutting operation,
develop an expression for the shear angle (ϕ) in terms of rake angle (α) and
cutting ratio (r). State any assumptions you make during the derivation of the
above expression.
The following data are collected from an orthogonal cutting operation:
Uncut chip thickness:
0.2 mm
Chip thickness:
0.25 mm
Rake angle:
10°
Cutting speed:
2.5 m/s
Determine the following;
i)
Shear angle for the above operation.
ii) The chip velocity.
2
(8 marks)
(4 marks)
(4 marks)
(2 marks)
(4 marks)
(3 marks)
(3 marks)
(3 marks)
(3 marks)
(8 marks)
(3 marks)
(3 marks)
4
a)
b)
Distinguish assembly charts from flow-process charts that are widely used in
process planning operations. Elaborate on your answer by taking suitable examples.
A company has the option of using either machine A or machine B for machining
a product. Table Q4 gives information on the machines.
Machine A
Machine B
60 000
75 000
Hourly operating cost (£)
12
10
Parts produced per hour
10
15
Initial cost (£)
Annual operational hours
for both machines (hrs)
(8 marks)
2500
Interest rate (%)
20
Table Q4
i)
ii)
5
a)
b)
c)
d)
e)
6
a)
b)
c)
d)
7
a)
b)
c)
d)
What machine would you select to produce the parts? Justify your answer.
If the company expects an annual output of 3000 parts, what machine would
you select? Justify your answer.
Distinguish between numerical control (NC) and computer numerical control (CNC)
machine tools widely used in the manufacturing industry.
Discuss at least four advantages of CNC over NC machine tools.
Illustrate how would you justify the economic benefits gained by implementing
NC/CNC technology in a manufacturing organisation?
Functions performed by Direct Numerical Control (DNC) systems are unique and
could not be accomplished either with conventional NC or with CNC systems.
Briefly explain at least four functions performed by DNC.
Explain two application areas of CNC technology in the manufacturing industry.
Distinguish between ‘Fixed zero’ and the ‘Floating zero’ coordinate systems in
NC machines.
Compare and contrast manual part programming and computer aided part
programming, stating any relative advantages and limitations, in relation to
programming of CNC machines.
Discuss three important stages in computer aided part programming procedure.
Explain the terms ‘preparatory function’ and ‘miscellaneous function’ in the
context of CNC part programme.
Distinguish between ‘computer-aided’ and ‘computer-integrated’ in the context
of manufacturing.
Computer aided design (CAD) offers superior performance in the design of
products over conventional design procedures. Explain how is this achievable?
The real potential of computer-aided design (CAD) and computer-aided
manufacturing (CAM) can be fully realised only by integrating them to form
CAD/CAM systems.
i)
Explain the operation of a CAD/CAM system.
ii) List four benefits that the above systems offer.
Illustrate by taking suitable examples, the two most commonly used solid
modelling techniques employed by CAD systems.
3
(6 marks)
(6 marks)
(4 marks)
(4 marks)
(6 marks)
(4 marks)
(2 marks)
(4 marks)
(8 marks)
(6 marks)
(2 marks)
(4 marks)
(4 marks)
(2 marks)
(2 marks)
(8 marks)
See next page
8
a)
b)
c)
d)
e)
Hard and soft automation are widely used for automating the manufacturing
process depending on the type of manufacturing system.
i)
Distinguish hard automation from soft automation.
ii) Discuss the applicability of the above two types of automation in
manufacturing industries.
Explain what is meant by a Flexible Manufacturing Systems (FMS).
Distinguish between a Flexible Manufacturing Unit (FMU) from a Flexible
Manufacturing Cell (FMC).
Discuss the application of industrial robotics in manufacturing.
An industrial robot is to be used to place integrated circuit chips on to a circuit
board. Select the type of robot based on the geometrical configuration suitable
for the above operation. Justify your answer.
4
(4 marks)
(2 marks)
(2 marks)
(4 marks)
(4 marks)
(4 marks)