More Preventive is Not Necessarily the Answer

More is not necessarily better when it comes to preventive maintenance you have to find the right amount done right with the right tools.

Lets first talk in extremes, there are some facilities that are truly reactive in nature and only fix equipment when it breaks. This keeps them very busy and leaves little time to do preventive (PM) or predictive (PdM) maintenance. This can lead them into a death spiral of unreliability. Many of these sites believe that if they could just get a bunch of PMs, then they will escape the spiral.

On the other side there are also other facilities that over time or in response to an incident have created a large portion of their backlog that consist of PM work and again they face many breakdowns and unreliability. If PMs are good why might these facilities experience an increase in breakdowns and unreliability?

One answer is infant mortality. In other words by doing more invasive PM inspections, such as opening a gear box to inspect the teeth, they actually induce failures. These failures can come from dirt and debris that accidentally gets into the box while it is open or improper reassembly upon completion. In this example many of the PdM tools could eliminate this PM activity in most cases and in turn eliminate the infant mortality issue entirely.

So the second enemy in more PMs is the possible loss of effectiveness because of low quality procedure, or poor execution in the field due to labor overload or has a lack of training on the added task. Many facilities ramp up the number of PMs by getting suggested PMs from vendors or coping other facilities PM procedure. This leads to task that don’t address the failure modes and in many case may not even address the equipment in question. 

So if you want to increase your level of preventive maintenance and your reliability take these steps:

1. Create a plan of what equipment and when. This could be based off of criticality.
2. Generate solid craftsman reviewed PM task that are failure mode based and detailed to the right level. You can base them off of example if they are reviewed and verified prior to deployment.
3. Finally use the predictive maintenance tools to eliminate the invasive preventive maintenance that plagues you by adding defects to your system.

Grow a good program a little at a time as apposed to a bad program overnight.