With preventive maintenance, parts of a machine or system are replaced on base of calendar time or operating hours. The OEM indicates when a component needs to be replaced to avoid failure, and thus a maximum return on the asset is achieved. This way of maintenance is also called periodic maintenance.

 

Benefits preventive maintenance

An advantage of this type of maintenance is the improved reliability. Many manufacturers have tested their products extensively and know when the product fails theoretically. The replacement interval is chosen at a rate of 1% or less of premature failure. In other words, more than 99% of the products do not fail prematurely. This is theoretically and in practice we see that this is not always the case.

Disadvantages preventive maintenance

A disadvantage is that regular parts are replaced long before they have reached their real lifetime. This causes a huge unnecessary expense. Despite preventive maintenance the risk remains of premature failure. The problem may be caused by a wrong assembly, manufacturing defects, improper lubrication or heavier load than had been expected.

Risk of preventive maintenance

A lofty phrase in relation to preventive maintenance is: "If it ain’t broken, don’t fix it". The condition of a machine can deteriorate by repairing it!