1. Maintenance McGraw-Hill/Irwin Copyright © 2012 by The McGraw-Hill Companies, Inc. All rights reserved.

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

3. Maintenance All activities that maintain facilities and equipment in good working order so that a system can perform as intended Maintenance activity categories: Buildings and grounds Equipment maintenance 14S-3 Student Slides

4. 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 14S-4 Student Slides

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 14S-5 Student Slides

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 14S-6 Student Slides

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 14S-7 Student Slides

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 Student Slides 14S-8

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 Student Slides 14S-9

10. Number of breakdowns0123 Frequency of occurrences.20.30.40.10 14S-10 Student Slides

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 average $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 14S-11 Student Slides

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 14S-12 Student Slides

13. Maintenance problems are sometimes designed into products: Poor design Designer have accorded other aspects of design greater importance Cost Appearance is more important than maintenance activities Student Slides 14S-13

14. 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 14S-14 Student Slides

15. 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 14S-15 Student Slides