14s-1Maintenance William J. Stevenson Operations Management 8 th edition

14s-2Maintenance CHAPTER 14s Maintenance McGraw-Hill/Irwin Operations Management, Eighth Edition, by William J. Stevenson Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved.

14s-3Maintenance 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

14s-4Maintenance  Reasons for keeping equipment running  Avoid production disruptions  Not add to production costs  Maintain high quality  Avoid missed delivery dates Maintenance Reasons

14s-5Maintenance  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

14s-6Maintenance Total Maintenance Cost Breakdown and repair cost Optimum Amount of preventive maintenance Cost Total Cost Preventive maintenance cost Table 14S.1

14s-7Maintenance  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 Maintenance

14s-8Maintenance 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 breakdowns0 123 Frequency of occurrence

14s-9Maintenance Number of Breakdowns Frequency of Occurrence Expected number of Breakdowns Expected cost to repair = 1.4 breakdowns per month X $1000 = $1400 Preventive maintenance = $1250 PM results in savings of $150 per month Example S-1 Solution

14s-10Maintenance 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

14s-11Maintenance 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 and readily available to diagnose and correct problems with equipment

14s-12Maintenance Replacement  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?