Past Papers

Question 1

A manufacturer decides to use open-die forging on a metal component initially made by Selective
Laser Sintering of steel powder. Which likely motivation could they have for this uncommon
sequence of operations?

Answer 1

A. Reduce cost
B. Increase residual stresses
C. Reduce porosity
D. None of the above
This would indeed be uncommon and impractical, but forging could be
used to compress the part, hence reduce or eliminate porosity in the
component.
SLS is an additive manufacturing technique that creates components by sintering powdered material using a laser. While this process allows for complex geometries and customization, it can lead to parts with internal porosity and less dense microstructures compared to traditional manufacturing methods.
Open-die forging involves deforming the metal between multiple dies that do not enclose the material completely. This process helps in refining the grain structure and improving the mechanical properties of the material.One of the main issues with SLS is the presence of porosity within the component. Open-die forging can help eliminate or significantly reduce these pores by applying high compressive forces, thereby increasing the density of the material.Forging improves the grain structure, enhances ductility, and increases strength. This leads to better overall mechanical properties of the component, making it more robust for demanding applications.Forging generally aims to reduce residual stresses, not increase them. The application of high temperatures and pressures during forging tends to relieve internal stresses rather than create them.
Using both SLS and open-die forging is not typically a cost-saving approach. It involves multiple processing steps and can be more expensive compared to using a single manufacturing method optimized for cost.

Question 2

You are asked to assess the process capability for a cooling system and
are told that the Upper Tolerance Limit for the temperature is 78 C. Which
capability index is best to assess this process?

Answer 2

Since we are referring to a cooling system and a Lower Tolerance Limit
appears to be irrelevant, the upper one-sided index is the most suitable.

Cpu (Capability Index for Upper Specification Limit): This index is specifically used to measure how well the process mean is centered relative to the upper specification limit. It is appropriate when only the upper limit is critical, and the primary concern is ensuring that the process does not exceed this upper limit.
Cpl (Capability Index for Lower Specification Limit): This index measures the capability relative to the lower specification limit. It is used when only the lower limit is of concern. Since you are given an upper tolerance limit, Cpl is not appropriate in this context.
Cpk (Process Capability Index): Cpk considers both the upper and lower specification limits and measures how centered the process is within these limits. It is useful when both limits are relevant. In this case, since only the upper limit is given, Cpk is not the most appropriate choice.
Cp (Process Capability): Cp measures the overall capability of the process by considering the spread of the process relative to the total specification range. It does not account for the centering of the process. Cp is best used when both upper and lower limits are specified and equally critical.

Question 3

You are employed by a furniture maker who asks you to estimate the cost of a metal table made
by a competitor. You are given some marketing information for the item in question and some
internal specifications and costings for oak tables made at your own factory. Given this
information, which method of costing is best suited for this task?
Parametric modelling
ABC
VBC
None of the above

Answer 3

By a process of elimination we can check that the three methods offered
above cannot be used with only the data given in the question. You could
however pursue a baseline method using the marketing information.
Parametric Modelling:

While parametric modelling is useful when you have a statistical relationship between cost and product parameters, it may not be fully applicable if the available data (from oak tables) doesn’t sufficiently correlate to the metal tables due to different materials, processes, and market conditions.
Activity-Based Costing (ABC):

ABC is more suitable for internal cost allocation and requires detailed information about the activities and processes, which you likely do not have for the competitor’s production methods.
Value-Based Costing (VBC):

VBC focuses on pricing based on customer perceived value rather than actual production costs, which is not directly useful for estimating competitor production costs.

Question 4

There are different classification approaches for Manufacturing Processes, depending on the
objective of the classification. In one such chart the following processes are listed in the same
category: resistance welding, electrical discharge machining, selective powder sintering. Which of
the following characteristics is shared between the three processes?
Electric voltage between the workpiece and tool is required
An additional cooling stage is required
They are all net-shape processes
None of the above

Answer 4

By a process of elimination we can go through each one of the
characteristics and find a process that does not fit the description. For
example, SLS does not require voltage, EDM does not require a separate
cooling step and EDM is not net-shape.
Resistance Welding: Yes, this involves electric current to create heat through resistance.
EDM: Yes, this involves electric discharges (sparks) between the electrode and workpiece.
Selective Powder Sintering (SLS): No, SLS typically uses a laser to sinter the powder, not electric voltage directly between workpiece and tool.Resistance Welding: Cooling might occur but is not a defining stage of the process.
EDM: Cooling can be part of the process to manage the heat generated, but not always required.
SLS: Typically, parts cool down naturally post-sintering but do not require a distinct cooling stage.Resistance Welding: This is a joining process, not a net-shape manufacturing process.
EDM: Can produce near-net shape parts, but often requires finishing.
SLS: This is a net-shape process, creating parts close to final geometry.

Question 5

When implementing the RPW method for line balancing, we assume activities are in a series,
following one-another. An assembly line consists of activities A ,…,A . How would you implement
the RPW when two activities (A and A ) need to happen at the same time?
Select one alternative:
1 12
3 5
Create two workstations with parallel operations
Merge A3 and A5 into one activity
Split the activities into two groups and perform the RPW twice
None of the above

Answer 5

As stated in the question, the RPW method only works for tasks in series.
Hence, we can comply with that requirement and satisfy the specific
conditions for A3 and A5 by merging them for the purposes of applying
RPW.

Question 6

Workers seen frequently chatting during their lunch break

Answer 6

Not waste

Question 7

Several repairs are needed because the maintenance technician cannot keep up with
demand.

Answer 7

Muri

Question 8

Orders for customized instruments force the line to slow down.

Answer 8

Mura

Question 9

Managers instructed workers to pause work and applaud every time a large order comes
in.

Answer 9

Muda

Question 10

A metal work apprentice without musical expertise was given the task of checking the
quality of the instruments.

Answer 10

Muri

Question 11

Suggest three arguments to convince the Airbass
managers to avoid updating the operation during the Industry 4.0 era.

Answer 11

• You will need to train your staff or hire new people. This is particularly
  challenging if the staff is used to a certain type of manual operation.
• Customers might prefer the traditional, manual approach for
  manufacturing musical instruments and might feel quality has
  deteriorated (even if that is not the case). Along the same vein,
  quality control for musical instruments might necessitate “traditional”
  techniques.
• Industry 5.0 is just around the corner… i.e. Machine Learning is
  entering manufacturing and it might be better to wait a few years
  before going for an update.
• There are always risks with major change.
• You will lose valuable experience with manufacturing techniques that
  might be unique to your operation or brand.

Question 12

Which of the following is an input capacity measure.

Answer 12

Number of rooms in hotel

Question 13

In a friction less environment, if the height of a spruce is 1.9 cm and the volume of mould cavity is 250.047 cm^3; what is the velocity of the molten metal leaving the gate (assume g=10 m/s^2) [in cm/s within 0.01 cm/s]?

Answer 13

61.64

Question 14

A serial manufacturing process making discrete parts is made of three consecutive processes. The average proportion of defective parts produced in these three operations is 0.07, 0.04 and 0.03. If the demand is 3300, what is the required capacity for the process?

Answer 14

3811

Question 15

In which of the following projects, PERT is NOT likely to generate good results?

Answer 15

A simple project with 15 tasks

Question 16

Which of the following layout types is suitable for making an aircraft carrier?

Answer 16

Fixed Position

Question 17

Which of these techniques relies on a supply of liquids to produce parts?

Answer 17

SLA

Question 18

Which of the following processes has the highest global output in terms of material volume?

Answer 18

Rolling

Question 19

Which of the following is not a typical property of continuous fibre reinforced polymers?

Answer 19

Recyclable
WA: Anisotropic, Inhomogeneous
Multi-material

Question 20

Common type of maintenance

Answer 20

Corrective, Breakdown NOT Short Term

Question 21

not a common type of
reinforcement fibres in composite laminate materials

Answer 21

Asbestos NOT Carbon, Glass

Question 22

Which of the following manufacturing processes uses sheet
material as feedstock?

Answer 22

LOM Laminate object manufacturing NOT SLS AND EBM which use powder

Question 23

Which of the following sentences describes a two-bin control
method

Answer 23

A system where an order is made when one bin is
empty, and the second bin is used during the lead
time NOT A system where the supplier always delivers two lots of
stock. A system where two bins of parts are used in parallel
to allow more workers efficient access

Question 24

Which of the following is an assumption of the Economic
Order Quantity model?

Answer 24

Delivery of stock is instantaneous.
NOT Demand is linearly increasing, order cost is a function of order size

Question 25

List and briefly explain one argument for and three arguments
against adding degrees of freedom to a machining system.

Answer 25

Adv: can handle more complex geometries. Adding degrees of freedom to a machining system increases its flexibility and capability to perform complex tasks. With more DoF, the machine can maneuver in more directions, allowing for the creation of more intricate and sophisticated parts. This is particularly beneficial in industries where precision and complexity are paramount
Disadv: Higher costs, increased complexity and maintenance, longer learning curve for operators, complex programming and set-up. More degrees of freedom make the system more complex, which can lead to higher maintenance requirements. Each additional DoF introduces more components that can wear out or fail, leading to increased downtime and maintenance costs. Additionally, diagnosing and repairing issues can become more difficult as the system becomes more intricate.Adding DoF typically requires more advanced machinery and control systems, which can significantly increase the initial cost of the equipment. The investment in more sophisticated technology might not always justify the return, especially for smaller manufacturing operations or those producing simpler products.Operating a machining system with more degrees of freedom can be more challenging and require highly skilled operators and programmers. The complexity of programming multi-DoF systems is higher, demanding more sophisticated software and greater expertise. This can lead to increased training costs and a steeper learning curve for operators, potentially slowing down production if not managed properly.

Question 26

You are a Mechanical Engineering undergraduate student
planning your final year project. The project requires you to
produce and test a prototype bicycle wheel which can be 3D
printed as a single product on an innovative new metal additive
manufacturing process.
(a) Explain three characteristics of this activity that suggest it can
be labelled as a “project”.

Answer 26

Focussed: Main objective of the project is limited to the wheel only
Unique: Testing a new metal additive manufacturing process
Uncertain: don’t know if the project will work or not
Temporary Nature with a Defined Timeline: Projects are defined by their finite duration, and once the prototype is produced and tested, the project will be considered complete.

Question 27

One of the assignments suggests you use a Gantt chart to plan
and track your progress. List three limitations of Gantt charts
with reference to the final year project planning.

Answer 27

False sense of certainty
Harder to update manually
Does not consider resource allocation:Limited Representation of Task Dependencies: While Gantt charts show start and end dates and the duration of tasks, they often fail to clearly represent the complexities of task dependencies and resource allocation. In your project, where certain tasks (e.g., testing the prototype) depend on the completion of others (e.g., 3D printing the prototype), the chart might not fully illustrate the critical paths and potential bottlenecks, leading to an oversimplified view of the project’s workflow.
Complexity and Overcrowding: Each task and its subtasks, along with their dependencies, might make the chart overly complex, making it challenging to understand and manage.

Question 28

You budget is limited to £300, therefore you need a good
projection of necessary expenditure. Describe three challenges
for the planned cost estimation of the expenditure.

Answer 28

Inexperienced analyst: as students, have no previous experience
New process: cannot estimate cost of what has never been done before
Complex technology
Uncertainty in Material Costs: rices for metals and other necessary materials can fluctuate based on market conditions, availability, and supplier pricing policies
Unexpected Technical Issues: During the production and testing phases, unforeseen technical issues can arise. These might include problems with the 3D printing process, defects in the prototype, or the need for additional iterations and modifications. Addressing these issues often requires additional resources and expenditures that were not initially planned for, straining the limited budget.
Ancillary Costs: There are often hidden or ancillary costs associated with a project like this. These can include expenses for software licenses, post-processing treatments, testing equipment, and even shipping if components need to be sent out for specialized work. Such costs are easy to overlook during initial budgeting but can significantly impact the overall expenditure if not properly accounted for.

Question 29

Which forming process does an FFF 3D printer typically employ?

Answer 29

Extrusion

Question 30

Most flexible

Answer 30

SLS NOT rolling flat die forging casting

Question 31

Cellular manufacturing is a widely applied factory layout for Batch manufacturing system. Which statement better describes resource grouping in a collection of manufacturing cells

Answer 31

By process requirements of parts NOT sequence of operations or process

Question 32

Quality can be defined in several ways, which is unsual

Answer 32

batch-size based NOT manufacturing, user and transcendent based

Question 33

Plant layout in manufacturing cars

Answer 33

Product NOT functional, fixed position, cellular

Question 34

Which family of processes affords more control over grain size in metals

Answer 34

Forging NOT casting SLS Deep drawing

Question 35

SLP does not involve what

Answer 35

maximising space availability NOT constructive a matrix for activities, determining the flow of materials between departments, ranking the flows between departments

Question 36

Forming of sheet metal and of polymer matrix composite are similar is ways but differ in others, which is erroneous?

Answer 36

both done is pressure controlled environment NOT both benefit from elevated temp, alter the mech properties of materials, neither require workpieces that have high resistance to electricity

Question 37

which measure of stored inventory can help us evaluate the impact of a disruption in the supply chain to our short term operations

Answer 37

stock cover NOT monetary value, stock turn

Question 38

According to the characteristics of Projects we discussed in ME20026,
which of the following activities would not be considered a Project?

Answer 38

The characteristics we gave in lecture were “focused; temporary; unique;
complex; uncertain”.A. Training for and running a marathon
B. Producing a group video for a coursework assignment
C. Repairing a damaged electronic device
NONE OF THE ABOVE

Question 39

Anisotropic

Answer 39

Properties vary depending on the direction in which they are
measured

Question 40

we introduced hand layup, filament winding and spray
layup. Which of those employs a lathe-like device to actuate the tooling?

Answer 40

Filament winding

Question 41

Which of the following is an advantage of metal casting processes for
aerospace applications?

Answer 41

A. Parts are not likely to require post-processing
B. Fine control of material properties
C. Minimal lead time
D. None of the above THIS

Question 42

Open-die forging is a notably flexible manufacturing process. Select the
product properties that cannot be controlled in open-die forging

Answer 42

A. Product geometry
B. Grain structure
C. Material porosity
D. None of the above THIS

Question 43

In resistance spot welding, which of the following functions is not
performed by the electrodes?

Answer 43

A. Pressure application
B. AC power supply
C. Heat transfer THIS
D. None of the above

Question 44

Which one of the following is an example of contact inspection?

Answer 44

A. Coordinate measuring systems THIS
B. Scanning laser systems
C. Machine vision systems
D. None of the above

Question 45

A complex product is being modified and reintroduced to your
manufacturing operation. You have access to the team that developed the
original product and production plan, but can only assign one of them to
the new project. Which worker is best equipped to help you?

Answer 45

A. Project manager THIS
B. Production engineer
C. Product designer
D. None of the above

Question 46

Which of the following is a new concern in Industry 4.0 compared to
conventional manufacturing.

Answer 46

A. Designs stolen by competitors
B. Flexible processes
C. Supply chains
D. None of the above THIS

Question 47

A customer is disappointed to find that the product manual appears to
have an erroneous diagram of the wireless headphones they just
purchased. This falls under which gap between customer expectations
and perceptions?

Answer 47

A. Concept-specification gap
B. Actual quality-communicated image gap
C. Quality specification-actual quality gap
D. None of the above THIS

Question 48

During a healthcare emergency, you need to produce large quantities
(hundreds of thousands) of ventilator valves in a very short time, while
addressing various other shortages. Which type of manufacturing facilities
should you employ?

Answer 48

A. Job shops
B. Cellular manufacturing
C. Mass production THIS
D. All of the above

Question 49

Just-in-time (JIT) does NOT include which one of the following?

Answer 49

A. Batch sizes of one
B. Fast-throughput manufacturing
C. High inventory production THIS
D. All of the above are included in JIT

Question 50

If you want to make sure that products and services are made to conform
with their specification, the first step is to:

Answer 50

A. Control quality against standards.
B. Define the relevant quality characteristics. THIS
C. Develop a measure for each quality characteristic.
D. None of the above.

Question 51

Which nondestructive testing technique is most appropriate in massmanufacturing facility for small components with cycle times under 1s,
when every part needs to be evaluated?

Answer 51

A. CMM
B. Ultrasonic techniques
C. Scanning laser systems THIS
D. None of the above

Question 52

Explain three ways in which a liquid hand soap manufacturer could
change the cylindrical packaging of its most popular product to reduce
its transportation costs.

Answer 52

• Nesting shapes (topological)
• Lower weight of packaging by making walls thinner (structural)
• Switch to a lighter material (density)

Question 53

List four indirect costs of operating the jobshop, adding any necessary
explanations.

Answer 53

There’s a large number of possible responses here: Rent, heat, light, power, management staff,
maintenance, depreciation, cleaning, transport, safety, computer network,…