14s-1maintenance william j. stevenson operations management 8 th edition
TRANSCRIPT
14s-1 Maintenance
William J. Stevenson
Operations Management
8th edition
14s-2 Maintenance
CHAPTER14s
Maintenance
McGraw-Hill/IrwinOperations Management, Eighth Edition, by William J. StevensonCopyright © 2005 by The McGraw-Hill Companies, Inc. All rights
reserved.
14s-3 Maintenance
IntroductionIntroduction
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
14s-4 Maintenance
Reasons for keeping equipment running Avoid production disruptions Not add to production costs Maintain high quality Avoid missed delivery dates
Maintenance ReasonsMaintenance Reasons
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 ConsequencesBreakdown Consequences
14s-6 Maintenance
Total Maintenance CostTotal Maintenance Cost
Breakdown andrepair cost
Optimum Amount of preventive maintenance
Co
st
Total Cost
Preventivemaintenance cost
Table 14S.1
14s-7 Maintenance
Preventive maintenance: goal is to reduce the 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 MaintenancePreventive Maintenance
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-1Example S-1
Number of breakdowns 0 1 2 3Frequency of occurrence .20 .30 .40 .10
14s-9 Maintenance
Number ofBreakdowns
Frequency ofOccurrence
Expected number ofBreakdowns
0123
.20
.30
.40
.101.00
0.30.80.30
1.40
Expected cost to repair = 1.4 breakdowns per month X $1000 = $1400Expected cost to repair = 1.4 breakdowns per month X $1000 = $1400Preventive maintenance = $1250Preventive maintenance = $1250PM results in savings of $150 per monthPM results in savings of $150 per month
Example S-1 SolutionExample S-1 Solution
14s-10 Maintenance
Predictive MaintenancePredictive 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
14s-11 Maintenance
Breakdown ProgramsBreakdown 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 and readily available to diagnose and correct problems with equipment
14s-12 Maintenance
ReplacementReplacement
Trade-off decisions Cost of replacement vs cost of continued maintenance New equipment with new features vs maintenance Installation of new equipment may cause disruptions Training costs of employees on new equipment Forecasts for demand on equipment may require new
equipment capacity When is it time for replacement?