What is Preventive Maintenance?

Preventive Maintenance (PM) is the process of performing actions in an effort to eliminate or reduce breakdowns and wear. If you've ever changed the oil or rotated tires on a car, you've performed a PM. When we use a PM system we are making an effort to find, reduce or prevent wear before it leads to Corrective Maintenance, i.e. breakdown. Perhaps more importantly than preventing breakdowns is keeping equipment in good running condition.

Let's consider the air pressure in the tires on a car. If we never check the air pressure, and therefore don't maintain a minimum pressure, eventually the pressure will go low enough, through microscopic leaks that are unavoidable, that performance, fuel economy, and safety become impacted. Further as it becomes harder for the mechanical steering systems to move the tires through their range of motion, due to increased resistance from an additional surface area contacting the road, the steering components get more wear. Now we've got tires wearing out prematurely directly increasing the cost to operate our car; we're getting reduced fuel economy further increasing costs; and our vehicle has become less safe to operate in that under-inflated tires run hotter and have a greater potential for blowout.

Additionally since we're putting more stress on steering components we are also reducing their lifespan, increasing costs, and increasing the likelihood of premature failure. Certainly this is a worst case scenario but definitely not out of the realm of possible or even probable.

This is why virtually every manufacturer of mechanical equipment has a schedule of recommended maintenance.