1. Maintenance Copyright © 2015 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.

2. 14S-2 You should be able to: LO 14S.1Explain the importance of maintenance in production systems LO 14S.2Describe the range of maintenance activities LO 14S.3Discuss preventive maintenance and the key issues associated with it LO 14S.4Explain breakdown maintenance and name the key issues associated with it LO 14S.5State how the Pareto phenomenon pertains to maintenance decisions

3. 14S-3 The goal of maintenance is to keep the production system in good working order at minimal cost Reasons for wanting to keep equipment and machines in good operating condition: 1. Avoid production or service disruptions 2. Not add to production or service costs 3. Maintain high quality 4. Avoid missed delivery dates LO 14S.1

4. 14S-4 1. Operations capacity is reduced, and orders are delayed 2. There is no output, but overhead continues, increasing the cost per unit 3. There are quality issues Output may be damaged 4. There are safety issues Employees or customers may be injured LO 14S.1

5. 14S-5 Reactive: Breakdown maintenance Dealing with breakdowns or problems when they occur Proactive: Preventive maintenance Reducing breakdowns through a program of lubrication, adjustment, cleaning, inspection, and replacement of worn parts LO 14S.2

6. 14S-6 The goal of preventive maintenance is to reduce the incidence of breakdown or failures in the plant or equipment to avoid the associated costs Loss of output Idle workers Schedule disruption Injuries Damage to other equipment, products, or facilities Repairs Inventories of spare parts Repair tools and equipment Repair specialists LO 14S.3

7. 14S-7 It is periodic It can be scheduled according to the availability of maintenance personnel and to avoid interference with operating schedules Maintenance is scheduled using some combination of 1. The result of planned inspections that reveal a need for maintenance 2. According to the calendar (passage of time) 3. After a predetermined number of operating hours LO 14S.3

8. 14S-8 The goal is to strike a balance between the cost of preventive maintenance and the cost of breakdown The amount of preventive maintenance, therefore, is a function of the expected frequency of breakdown, the cost of breakdown, and the cost of preventive maintenance LO 14S.3

9. 14S-9 The frequency of breakdown of a machine per month is $1,000 and the cost of preventive maintenance is $1,250 per month. If preventive maintenance is performed, the probability of a machine breakdown is negligible. Should the manager use preventive maintenance, or would it be cheaper to repair the machine when it breaks down? Number of breakdowns0123 Frequency of occurrences.20.30.40.10 LO 14S.3

10. 14S-10 Number of breakdowns0123 Frequency of occurrences.20.30.40.10 LO 14S.3

11. 14S-11 Suppose the average time before breakdown is normally distributed with a mean of 3 weeks and a standard deviation of.60 weeks. If breakdown cost averages $1,000 and preventive maintenance costs $250, what is the optimal maintenance interval? Find the number of standard deviations from the mean represented by an area under the normal curve of.25 Using the standard normal table, it is -0.67 Use this value to determine the maintenance interval LO 14S.3

12. 14S-12 Predictive maintenance An attempt to determine when best to perform preventive maintenance activities Ideally, preventive maintenance will be performed just prior to a breakdown or failure because this will result in the longest possible use of facilities or equipment without a breakdown Total productive maintenance JIT approach where workers perform preventive maintenance on the machines they operate LO 14S.3

13. 14S-13 Approaches to dealing with breakdowns: Use of standby or backup equipment Inventories of spare parts are maintained Use operators who are able to perform at least minor repairs on the equipment they operate Have repair people who are well trained and readily available to diagnose and correct problems LO 14S.4

14. 14S-14 When breakdowns become frequent and/or costly: What is the cost of replacement compared to continued maintenance? Issues: Predicting breakdowns Technological change System disruptions Training employees on the use of new equipment Forecast of future demand LO 14S.4

15. 14S-15 Breakdown programs are most effective when they take into account the degree of importance of a piece of equipment has in the operations system, and the ability of the system to do without it for a period of time. The Pareto phenomenon exists in such situations: Few pieces of equipment will be extremely important to the functioning of the system These justify considerable effort and/or expense Some will require moderate effort and/or expense Many will justify minimal effort and/or expense LO 14S.5