Solutions Manual - Management Twelfth Edition Global Edition By Ja...

Solutions Manual For Principles of Operations Management Twelfth Edition Global Edition By Jay Heizer Barry Render Chuck Munson All Chapters 1-17, 100% Original Verified, A+ Grade.

All Chapters Arranged Reverse: 17-1

This is The Only Original and Complete Solutions Manual for 12 th Global Edition, All other files in the Market are Fake/Old/Wrong Edition. 1 / 4

168 CHAPTER 17 MA I N T E N A N C E A N D RE L I A B I L I T Y

C H A P T E R

Maintenance and Reliability

DISCUSSION QUESTIONS

1. The objective of maintenance and reliability is to maintain the capability of the system while controlling costs.

LO 17.5: Describe how to improve maintenance

AACSB: Application of knowledge

2. Candidates for preventive maintenance can be identified by looking at the distributions for MTBF (mean time between failures). If the distributions have a small standard deviation, they are usually a candidate for preventive maintenance.

LO 17.6: Compare preventive and breakdown maintenance costs

AACSB: Reflective thinking

3. Infant mortality refers to the high rate of failures that exists for many products when they are relatively new.

LO 17.5: Describe how to improve maintenance

AACSB: Analytical thinking

4. Simulation is an appropriate technique with which to investigate maintenance problems because failures tend to occur randomly, and the probability of occurrence is often described by a probability distribution that is difficult to employ in a closed-form mathematical solution.

LO 17.5: Describe how to improve maintenance

AACSB: Analytical thinking

5. Training of operators to perform maintenance may improve morale and commitment of the individual to the job or organization. On the other hand, all operators are not capable of performing the necessary maintenance functions or they may perform them less efficiently than a specialist. In addition, it is not always cost effective to purchase the necessary special equipment for the operator’s use.

LO 17.7: Define autonomous maintenance

AACSB: Application of knowledge

6. Some ways in which the manager can evaluate the effectiveness of the maintenance function include:

Maintenance productivity as measured by:

Units of production Maintenance hours

or:

Maintenance hours Replacement cost of investment ©2023 Pearson Education, Ltd. 2 / 4

169 CHAPTER 17 MA I N T E N A N C E A N D RE L I A B I L I T Y

or:

Actual maintenance hours to do job Standard maintenance hours to do job

Machine utilization as measured by:

( ) ( )

• )

A B C D

A B

  



where:

A  total available operating hours B scheduled downtime C scheduled mechanical downtime D nonscheduled mechanical downtime

Effectiveness of preventive maintenance as measured by:

Emergency maintenance hours 1 Preventative maintenance hours 

LO 17.5: Describe how to improve maintenance

AACSB: Analytical thinking

 7. Machine design can ameliorate the maintenance problem by, among other actions, stressing component reliability, simplicity of design and the use of common or standard components, simplicity of operation, and provision of appropriate product explanations and user instructions.

LO 17.2: Determine system reliability

AACSB: Reflective thinking

 8. Information technology can play a number of roles in the maintenance function, among them: Files of parts and vendors Management of data regarding failures Active monitoring of system states Problem diagnosis and tracking Via simulation—pretesting and evaluation of maintenance policy Enabling more precise control to reduce the likelihood of failure Enabling improved system design

LO 17.4: Distinguish between preventive and breakdown maintenance

AACSB: Application of knowledge

 9. The best response would probably be to enumerate the actual costs, both tangible and intangible, for each practice.

Costs of waiting until it breaks to fix it might include:

Unnecessary damage to the machine Significant downtime on the production line Random interruption of the production schedule Ruined raw materials Poor quality of products produced in a time period prior to breakdown Frustration of employees Costs to repair the machine Costs of preventive maintenance would include primarily the cost to replace the machine component. Downtime could be scheduled to reduce its cost; and the frustration of employees, etc., would certainly be less than incurred when the breakdown occurs.

LO 17.4: Distinguish between preventive and breakdown maintenance

AACSB: Application of knowledge

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CHAPTER 17 MA I N T E N A N C E A N D RE L I A B I L I T Y 170

10. Only when preventive maintenance occurs prior to all outliers of the failure distribution will preventive maintenance preclude all failures. Even though most breakdowns of a component may occur after time t, some of them may occur earlier. The earlier breakdowns may not be eliminated by the preventive maintenance policy. A distribution of natural causes exists.

LO 17.5: Describe how to improve maintenance

AACSB: Reflective thinking

ETHICAL DILEMMA

Yes, as the man said: “You can be perfectly safe and never get off the ground.” NASA’s website states, “Humans are driven to explore the unknown, discover new worlds, push the boundaries of our scientific and technical limits, and then push further.” But the significant question for this ethical dilemma is: “Do we need to send men and women into space?” Given the sophistication and success evidenced in automation, simulation, drones, the Mars Lander, Curiosity etc., is staffed space travel necessary? And this is without considering the risk, which from a reliability perspective and in practice is huge and documented with the cost of many lives. Additionally, sending people into space drives the cost to astronomical levels (excuse the pun). There seems little doubt that men and women are put at risk for publicity, domestic politics, and geopolitical reasons. And people leave a lot of junk out there that creates other problems for unstaffed space travel and satellites, whose value has been documented. Should we keep sending people?ACTIVE MODEL EXERCISES (available in MyLab Operations Management)

ACTIVE MODEL 17.1: Series Reliability

1. Would it be better to increase the worst clerk’s reliability from .8 to .81 or the best clerk’s reliability from .99 to 1?Increase the worst clerk’s reliability from .8 to .81.

2. Is it possible to achieve 90% reliability by focusing on only one of the three clerks?No—the best we can do is 89.1% reliability, even with R2 to 100%.

ACTIVE MODEL 17.2: Redundancy

1. If one additional clerk were available, which would be the best place to add this clerk as back-up?At R2, yielding a system reliability of 97.23%.

2. What is the minimum number of total clerks that need to be added as backup in order to achieve a system reliability of 99%?Three more clerks—one more at each process.

ACTIVE MODEL 17.3: Parallel Systems

1. What is the reliability if only the top two parallel series are used?With the reliability of the bottom path set to 0.0, reliability is .9975.

2. What is the reliability if only the bottom two parallel series are used?With the reliability of the top path set to 0.0, reliability is .9975.

3. What is the reliability if only the top and bottom components are used?With the middle pair of components set to 0.0, reliability is .9975.

4. What is the reliability if components 2 and 3 have reliability of only .95?With the reliability of the middle pair set to .95 (all at .95), reliability is .99976.

5. What would the reliability of component 1 need to be to increase the overall reliability to .9999?Component 1 would need to be set to .958 for the system to have a reliability of .9999.

6. Suppose that components 2 and 3 both must have the same reliability. What does that need to be in order to have an overall reliability of .9999?To have a system reliability of .9999, components 2 and 3 must be set  .979.©2023 Pearson Education, Ltd.

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