BUSI2047 SUPPLY CHAIN & OPERATIONS PLANNING
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A LEVEL 2 MODULE, SPRING 2022-23 First Sit Exam Paper
BUSI2047 SUPPLY CHAIN & OPERATIONS PLANNING
SECTION A
Question 1. Short questions: (Answer only five parts of this question and use diagrams to illustrate your answers where appropriate. There is no word limit for the numerical questions but the descriptive questions carry a word limit of 250 words each. Do not just copy text or diagrams from books or the lecture slides but rephrase using your own words.)
a) What is safety stock, why is it important and what characteristics impact on the amount of safety stock a company should hold? [20%]
b) A manufacturing company has a choice of using one of two machines to fulfil the demand of a particular part. Machine 1 has a production capacity of 170 parts per day; machine 2 has a production capacity of 280 parts per day. The part has a constant demand of 80 parts per day. Which machine would you recommend for producing this part (and why)? Assume that both machines have the same setup cost and that the inventory holding cost is the same irrespective of the machine that produces the part. [20%]
c) A manufacturing company assembles product A (end item). Product A is composed of: two of items B; three of items C and one item D. Item C is composed of: two of items D and one items E. The production and assembly lead times are as follows: items A, B and C: 1 week each; items D and E: 2 weeks each. The master production schedule for product A for weeks 5 through to 10 is shown in the table below:
Week |
5 |
6 |
7 |
8 |
9 |
10 |
Demand |
70 |
110 |
30 |
80 |
50 |
140 |
The projected inventory for A at the end of week 4 is 15 units. The projected inventory for D at the end of week 2 is 90 units. In addition, 105 units of C and 30 units of D are expected to arrive in week 4. Draw the product structure diagram of product A and use an MRP approach to find the planned order release (lot-for-lot) for item D. Briefly
explain the steps in your calculations. [20%]
d) Suppose that the planned order release (POR) for component X is as follows:
Week |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
POR for X |
40 |
30 |
70 |
100 |
30 |
15 |
0 |
25 |
100 |
The weekly production capacity for component X is 65 units. Obtain your best capacity feasible plan given that the holding cost for X is £0.75 per unit per week and the production set-up cost is £140. Explain you approach and calculate the cost of your
plan and the weekly ending inventories of component X. [20%]
e) Explain how a KANBAN system operates . How do Just- in-Time (JIT) systems incorporate KANBAN principles? [20%]
f) Explain why the backward flow of information in a supply chain is vitally important for effective supply chain and operations planning. [20%]
g) Explain the differences between qualitative (subjective) forecasting methods and quantitative (objective) forecasting methods. [20%]
h) What is effective capacity and why should it always be the basis for capacity planning in operations and supply chain management? [20%]
SECTION B
(Answer one question from Section B. There is no word limit for Section B questions. Excel
screenshots are allowed but make sure that you explain how everything is calculated.)
2. Company ABC produces three products (product A, B and C). The demand forecasts for these products over a 6 months horizon together with the number of working days in each month are shown in the table below. At the start of month 1, 300 units of A, 140 units of B and 20 units of C are available in inventory. Product A requires 2 hours of labour time, product B requires 5 hours of labour time and product C requires 12 hours of labour time. The company currently employs 55 workers, each working 8 hours per day. These workers can only be hired/fired at the start of each month. Hiring additional workers costs £2000 per worker. Firing workers costs £4000 per worker. The regular labour cost is £22 per hour (8 hours per day). These workers can also do overtime at a cost of £28 per hour but for at most 2 hours per day. If necessary, flexible agency workers (with no hiring/firing cost) can be used to meet some of the staffing requirements at a cost of £50 per hour. The inventory holding cost per aggregate unit of production is £0.44 per month.
Month |
Working days |
Forecast prod A |
Forecast prod B |
Forecast prod C |
1 |
22 |
2500 |
1250 |
240 |
2 |
20 |
2600 |
680 |
380 |
3 |
16 |
2000 |
1625 |
110 |
4 |
24 |
3400 |
745 |
275 |
5 |
21 |
3400 |
835 |
126 |
6 |
19 |
1800 |
375 |
45 |
Using all the information above, develop your own (best possible) aggregate production plan with no shortages. Explain how you define and calculate aggregate units of production; explain the logic or rationale in your plan as well as all assumptions and calculations; calculate workforce, production and inventory levels as well as the cost of your plan and visualise the plan through an appropriate diagram. [100%]
3. The historical monthly demands and forecasts for product X are shown in the table below.
Month |
Demand |
Forecast |
1 |
536 |
530 |
2 |
505 |
533 |
3 |
510 |
524 |
4 |
492 |
515 |
5 |
380 |
508 |
6 |
340 |
498 |
7 |
320 |
490 |
8 |
315 |
484 |
9 |
296 |
476 |
10 |
270 |
465 |
(a) Make a time plot of the demand history and comment on the characteristics of
this time series. Using the forecasts and demand data, calculate the average error, MAPE, MAD and comment on the accuracy of the given forecasts for this time series. [30%]
(b) Apply a suitable forecasting technique to predict the demand for months 1
through to 10 in the table above. Explain all the steps and assumptions that you make in your calculations (e.g. values for smoothing coefficients and/or initial values for intercept and/or slope levels and/or seasonal coefficients). Calculate the average error and MAPE using your new forecasts and compare with those
obtained in part (a). [60%]
(c) Apply your forecasting approach from part (b) to predict, at the end of month 10, the demand for product X in months 11, 12 and 13. [10%]
SECTION C
(Answer one question from Section C. The total word limit for Section C questions is 1000 words.)
4. (a) The Bullwhip effect may cause stockouts and/or over-stock positions in a supply chain. Explain why and illustrate the Bullwhip effect in a diagram you draw yourself. Explain the different collaboration approaches that may be used to reduce or eliminate Bullwhip effects in a supply chain. [60%]
(Word limit: 600 words)
(b) Provide an example to explain when the Drum-Buffer-Rope (DBR) method of operations scheduling and control might be used in a production system and explain
how the method might be applied in your example. [40%]
(Word limit: 400 words)
5. (a) What is the Customer Order Decoupling Point (CODP) and why is important in supply chain and operations planning? [25%]
(Word limit: 250 words.)
(b) Company A manufactures sofas, armchairs and three-piece suites in many variants, colours and material types, which are sold through many retail outlets in the UK. Company B is a high-volume manufacturer of plastic buckets for domestic use that are produced in different sizes and colours and sold through DIY outlets and supermarkets across the UK. Company C manufactures many types of large motorised agricultural machinery used on farms and it sells its machinery around the world through third- party dealers and distributors. All three companies have their main production facilities in Nottingham.
Briefly advise each of the three companies on whether they should use a Make-to- Stock (MTS), Assemble-to-Order (ATO), Make-to-Order (MTO), or Engineer-to-Order (ETO) approach or some combination of these to manage their operations. In your answer, use the information given above, note any assumptions you make and what
other information you might seek from each company. [75%]
(Word limit: 750 words.)
2023-05-29