17
C H A P T E R
Maintenance and Reliability
DISCUSSION QUESTIONS
1. The objective of maintenance and reliability is to maintain the
2. Candidates for preventive maintenance can be identified
by looking at the distributions for MTBF (mean time between
AACSB: Analytical thinking
4. Simulation is an appropriate technique with which to investi-
AACSB: Analytical thinking
5. Training of operators to perform maintenance may improve
morale and commitment of the individual to the job or organiza-
tion. On the other hand, all operators are not capable of perform-
6. Some ways in which the manager can evaluate the effective-
Maintenance hours
Replacement cost of investment
or:
Actual maintenance hours to do job
Standard maintenance hours to do job
()
AB
−
where:
AACSB: Analytical thinking
LO 17.2: Determine system reliability
AACSB: Reflective thinking
8. Information technology can play a number of roles in the
maintenance function, among them:
failure
9. The best response would probably be to enumerate the actual
costs, both tangible and intangible, for each practice.
274 CHAPTER 17 MAI NTENA N CE AN D RE L I A BI L I T Y
◼ Random interruption of the production schedule
◼ Ruined raw materials
◼ Costs to repair the machine
occur after time t, some of them may occur earlier. The earlier
AACSB: Reflective thinking
There seems little doubt that men and women are put at risk for
publicity, domestic politics, and geopolitical reasons. And people
ACTIVE MODEL EXERCISES (AVAILABLE IN MYOMLAB)
ACTIVE MODEL 17.1: Series Reliability
2. Is it possible to achieve 90% reliability by focusing on only
ACTIVE MODEL 17.2: Redundancy
1. If one additional clerk were available, which would be the
2. What is the minimum number of total clerks that need to be
ACTIVE MODEL 17.3: Parallel Systems
1. What is the reliability if only the top two parallel series are used?
2. What is the reliability if only the bottom two parallel series
5. What would the reliability of component 1 need to be to
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
17.2 From Figure 17.2, about 13% overall reliability (or .995400)
17.3 Let R equal the reliability of the components. Then
17.4 (a) Percent of failures [FR(%)]
( )
5
% 0.05 5.0%
100
F= = =
(b) Number of failures per unit hour [(FR(N)]:
where
Non-operating time = (2,500 hrs) (5 units) = 12,500
55
() 500,000 12,500 487,500
FR N ==
−
Failure/unit-year = FR(N) 24 hr/day 365 days/yr
276 CHAPTER 17 MAI NTENA N CE AN D RE L I A BI L I T Y
17.18 E(breakdowns/year) = 0.1(0) + 0.1(1) + 0.25(2) + 0.2(3)
17.24* First, find the cost of the breakdowns without the
