1. Chapter 16 Supplement
Maintenance

2. Introduction Maintenance Breakdown maintenance Preventive 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

3. Reasons for keeping equipment running
Maintenance Reasons
Reasons for keeping equipment running
Avoid production disruptions
Not add to production costs
Maintain high quality
Avoid missed delivery dates

4. Breakdown Consequences
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

5. Total Maintenance Cost
Table 16S-1
Breakdown and repair cost
Optimum Amount of
preventive maintenance
Demand
Total Cost
Preventive maintenance cost

6. Preventive 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

7. Frequency of breakdown
Example S-1
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 use preventive maintenance?
Number of breakdowns 1 2 3
Frequency of occurrence
.20
.30
.40
.10

8. Example S-1 Solution Number of Breakdowns Frequency of Occurrence
Expected number of 1 2 3
.20
.30
.40
.10
1.00
.80
1.40
Expected cost to repair = 1.4 breakdowns per month X $1000 = $1400
Preventive maintenance = $1200
PM results in savings of $150 per month

9. 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

10. 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

11. When is it time for 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?