Chap014s Maintenance

7/28/2019 Chap014s Maintenance

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14s-1 Maintenance

William J. Stevenson

Operations Management

8th edition


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14s-2 Maintenance

CHAPTER

14s

Maintenance

McGraw-Hill/Irwin

Operations Management, Eighth Edition, by William J. StevensonCopyright 2005 by The McGraw-Hill Companies, Inc. All rights reserved.


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14s-3 Maintenance

Introduction

Maintenance All activities that maintain facilities and equipment in

good working order so that a system can perform as

intended

Breakdown maintenance

Reactive approach; dealing with breakdowns or

problems when they occur

Preventive maintenance Proactive approach; reducing breakdowns through a

program of lubrication, adjustment, cleaning,

inspection, and replacement of worn parts


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14s-4 Maintenance

Reasons for keeping equipment running Avoid production disruptions

Not add to production costs

Maintain high quality Avoid missed delivery dates

Maintenance Reasons


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14s-5 Maintenance

Production capacity is reduced Orders are delayed

No production

Overhead continues

Cost per unit increases

Quality issues

Product may be damaged

Safety issues

Injury to employees

Injury to customers

Breakdown Consequences


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14s-6 Maintenance

Total Maintenance Cost

Breakdown and

repair cost

Optimum Amount of

preventive maintenance

Cost

Total Cost

Preventive

maintenance cost

Table 14S.1


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14s-7 Maintenance

Preventive maintenance: goal is to reducethe incidence of breakdowns or failures in

the plant or equipment to avoid the

associated costs Preventive maintenance is periodic

Result of planned inspections

According to calendar

After predetermined number of hours

Preventive Maintenance


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14s-8 Maintenance

Frequency of breakdown

If the average cost of a breakdown is $1,000,

and the cost of preventative maintenance is

$1,250 per month, should we use preventive

maintenance?

Example S-1

Number of breakdowns 0 1 2 3

Frequency of occurrence .20 .30 .40 .10


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14s-9 Maintenance

Number ofBreakdowns Frequency ofOccurrence Expected number ofBreakdowns

0

1

2

3

.20

.30

.40

.10

1.00

0

.30

.80

.30

1.40

Expected cost to repair = 1.4 breakdowns per month X $1000 = $1400Preventive maintenance = $1250PM results in savings of $150 per month

Example S-1 Solution


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14s-10 Maintenance

Predictive Maintenance Predictive maintenance

An attempt to determine when best to perform

preventive maintenance activities

Total productive maintenance

JIT approach where workers perform

preventive maintenance on the machines they

operate

1 11


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14s-11 Maintenance

Breakdown Programs Standby or backup equipment that can be

quickly pressed into service

Inventories of spare parts that can be installed

as needed Operators who are able to perform minor

repairs

Repair people who are well trained andreadily available to diagnose and correct

problems with equipment

14 12 M i


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14s-12 Maintenance

Replacement

Trade-off decisions Cost of replacement vs cost of continued

maintenance

New equipment with new features vs

maintenance

Installation of new equipment may causedisruptions

Training costs of employees on new equipment Forecasts for demand on equipment may require

new equipment capacity

When is it time for replacement?

Chap014s Maintenance

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