# designing managing and improving operations

Review the attached Word document and answer each question. Please show work. Powerpoint presentation of lesson is also attached.

INFO 564 Homework Assignment-2

Question 1 (40 pts)

The following tasks have to be performed on a unit of raw material in order to convert it into a unit of finished product.

 Task Time (minutes) Immediate Predecessors a 3 — b 4 — c 3 a, b d 7 c e 7 c f 6 c g 9 e, f h 10 d, e i 3 g, h j 6 i Total 58
• Draw a precedence network for these tasks. (5 pts)
• Suppose that each task is performed at a separate station.The time taken is as shown in the above table.Once a task is performed it is picked up by the next station.Transfer times are included in the task times and so may be ignored.Thus you have an assembly line with 10 stations.
• It is possible to achieve the same production as in (b) with fewer stations.Suggest one possible arrangement that will do so.What is the efficiency of this arrangement? (10 pts)
• Suppose that a production of 40 units per 8-hour day is desired.

(i) What is the maximum production possible from this assembly line?(Hint: what is the bottleneck?) (5 pts)

(ii) what is the efficiency of this assembly line? (5 pts)

(i) What is the minimum number of stations needed to meet this rate? (2 pts)

(ii) Design an assembly line that will meet this requirement.(10 pts)

(iii) What is the efficiency of this line? (3 pts)

Question 2 (30 pts)

A machine has a setup time of 150 minutes and run time of 0.0075 minutes per piece.Order sizes are typically 10,000 pieces.After a batch is processed, the process has to be stopped and the machine has to be setup before the next batch can be processed.Assume that a day consists of two shifts and each shift is 450 minutes long.

Find the capacity in pieces per day for this machine under the following assumptions:

(i) A batch can consist of only one order; it cannot have other orders in it. (8 pts)

(ii) Three orders are combined to form a batch. (8 pts)

(iii) All orders can be combined into one batch. (8 pts)

(iv) What is the percent change in capacity as you go from (i) to (ii) to (iii)? (6 pts)

Question 3 (10 pts)

A particular operation may be performed by two kinds of process.Process A requires a setup time of 40 minutes, whereas Process B requires a setup time of 180 minutes.On the other hand, the per unit run times are: 0.015 minutes on A and 0.0023 minutes on B.Which batch sizes would you route to A and which ones to B?

Question-4 (20 pts)

A process produces two types of products A and B.Product A is done in batches of 1000 units.It involves a setup time of 2 hours and a run time of 75 seconds.Product B is done in batches of 500 units and involves a setup time of 1 hour and a run time of 45 seconds.

How many units can this process produce in a week of 40 hours, if:

• only product A is produced? (5 pts)
• only product B is produced? (5 pts)
• A and B are produced in a mix of 25% A and 75% B? (10 pts)