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 12th Global Edition,
All other files in the Market are
Fake/Old/Wrong Edition.
,168 CHAPTER 17 MAINTENANCE AND RELIABILITY
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.
,169 CHAPTER 17 MAINTENANCE AND RELIABILITY
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
©2023 Pearson Education, Ltd.
, CHAPTER 17 MAINTENANCE AND RELIABILITY 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.
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 12th Global Edition,
All other files in the Market are
Fake/Old/Wrong Edition.
,168 CHAPTER 17 MAINTENANCE AND RELIABILITY
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.
,169 CHAPTER 17 MAINTENANCE AND RELIABILITY
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
©2023 Pearson Education, Ltd.
, CHAPTER 17 MAINTENANCE AND RELIABILITY 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.
