Product Management and Operational Assignment PDF

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Product Management and Operational Assignment of a company, given by mgt faculty on week 2 of the final exam....

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13.1 A company currently using an inspection process in its material receiving department is trying to install an overall cost reduction program. One possible reduction is the elimination of one inspection position. This position tests material that has a defective content on the average of 0.04. By inspecting all items, the inspector is able to remove all defects. The inspector can inspect 50 units per hour. The hourly rate including fringe benefits for this position is $9. If the inspection position is eliminated, defects will go into product assembly and will have to be replaced later at a cost of $10 each when they are detected in final product testing. a. Should this inspection position be eliminated? b. What is the cost to inspect each unit? c. Is there benefit (or loss) from the current inspection process? How much? Answer: a. Average= 0.04 Inspection rate= 50/hour Number of defects per hour= 0.04*50 = 2 defects per hour Cost of inspection per hour= $9 Without inspection, cost for 2 defects would be = 2*$10 = $20 Eliminating the inspection, cost would be $20, which is more than the cost of inspection of $9. Thus, inspection should not be eliminated. b. Cost to inspect each unit= inspection cost/number of pieces inspected = $9/50 = $0.18 c. Since the current inspection process costs less than elimination of inspection, the current inspection process is benefitting. Benefit for 50 units = $(20-9) = $11 Benefit per unit = $11/50 = $0.22 13.9 Resistors for electronic circuits are manufactured on a high-speed automated machine. The machine is set up to produce a large run of resistors of 1,000 ohms each. To set up the

machine and to create a control chart to be used throughout the run, 15 samples were taken with four resistors in each sample. The complete list of samples and their measured values are as follows.

Develop an X 1 chart and an R-chart and plot the values. From the charts, what comments can you make about the process? Answer: X chart: Sample no. 1

Average XDbar 993 999.1

2

998.5

999.1

3

1004

999.1

UCL

LCL

1016.78 7 1016.78 7 1016.78

981.413 4 981.413 4 981.413

4

1010.5

999.1

5

1007.5

999.1

6

998.5

999.1

7

995.75

999.1

8

994.75

999.1

9

1001.75

999.1

10

996

999.1

11

997

999.1

12

1004.25

999.1

13

991

999.1

14

991

999.1

15

1003

999.1

7 1016.78 7 1016.78 7 1016.78 7 1016.78 7 1016.78 7 1016.78 7 1016.78 7 1016.78 7 1016.78 7 1016.78 7 1016.78 7 1016.78 7

4 981.413 4 981.413 4 981.413 4 981.413 4 981.413 4 981.413 4 981.413 4 981.413 4 981.413 4 981.413 4 981.413 4 981.413 4

X-Chart 1020 1015 1010 1005 1000 995 990 985 980

1

2

3

4

5

6

Average

7

8

9

10

X-Dbar

UCL

11

12 LCL

R chart: Sample no. 1

Range

R-bar

UCL

LCL

25 15

3

25

4

22

5

26

6

11

7

38

8

15

9

18

10

28

45.8573 3 45.8573 3 45.8573 3 45.8573 3 45.8573 3 45.8573 3 45.8573 3 45.8573 3 45.8573 3 45.8573 3

0

2

21.7333 3 21.7333 3 21.7333 3 21.7333 3 21.7333 3 21.7333 3 21.7333 3 21.7333 3 21.7333 3 21.7333 3

0 0 0 0 0 0 0 0 0

13

14

15

11

17

12

28

13

22

14

15

15

21

21.7333 3 21.7333 3 21.7333 3 21.7333 3 21.7333 3

45.8573 3 45.8573 3 45.8573 3 45.8573 3 45.8573 3

0 0 0 0 0

R-Chart 50 45 40 35 30 25 20 15 10 5 0

1

2

3

4

5

6 Range

7

8 R-bar

9

10 UCL

11

12

13

14

15

LCL

Neither in the X chart nor in the R chart, the value exceeded the UCL or the LCL, so there is no problem with the sample values. 13.10 You are the newly appointed assistant administrator at a local hospital, and your first project is to investigate the quality of the patient meals put out by the food-service department. You conducted a 10-day survey by submitting a simple questionnaire to the 400 patients with each meal, asking that they simply check off that the meal was either

satisfactory or unsatisfactory. For simplicity in this problem, assume that the response was 1,000 returned questionnaires from the 1,200 meals each day. The results are as follows.

a. Using a z-value of 2.00, construct a p-chart based on the questionnaire results, using a confidence interval of 95.5 percent. b. What comments can you make about the results of the survey? Answer: a. p 0.074

p bar 0.06

0.042

0.06

0.064

0.06

0.08

0.06

0.04

0.06

0.05

0.06

UCL p 0.0750 2 0.0750 2 0.0750 2 0.0750 2 0.0750 2 0.0750

LCL p 0.0449 8 0.0449 8 0.0449 8 0.0449 8 0.0449 8 0.0449

0.065

0.06

0.07

0.06

0.04

0.06

0.075

0.06

2 0.0750 2 0.0750 2 0.0750 2 0.0750 2

8 0.0449 8 0.0449 8 0.0449 8 0.0449 8

P chart 0.08 0.07 0.06 0.05 0.04 0.03

1

2

3

4 p

5 p bar

6 UCL p

7

8

9

10

LCL p

b. Since the values have crossed both the upper limit and lower limit, the whole process needs and investigation and improvement so that the value does not cross any of the upper or lower limits. 13.15 Large-scale integrated (LSI) circuit chips are made in one department of an electronics firm. These chips are incorporated into analog devices that are then encased in epoxy. The yield is not particularly good for LSI manufacture, so the AQL specified by that department is 0.15, while the LTPD acceptable by the assembly department is 0.40. a. Develop a sampling plan. b. Explain what the sampling plan means; that is, how would you tell someone to do the test? Answer:

a. LTPD acceptable by the assembly department is 0.40 which means that the company will reject 60% of the time. AQL is the acceptable quality level, opposite of LTPD and has a value of 0.15 which means the buyer will accept a defect of till 15%. So, in this plan we have to take samples and then inspect the samples to see if there are defects or not. We will record the number of defects. If the number of defects is less than the acceptable level, the buyer will accept all of the products from the samples tested. If the number of defects is more than the acceptable level, it will be returned back to be fixed. b. We can take a number of 100 chips for every sample size. We will have to attach the circuit chips to the circuits and check whether there are any defects or not. From there we will have to calculate the percentage of defects per every 100 samples, and take the decision by matching with the acceptable quality level and Lot Tolerance Percent Defective....