6 steps - How to develop a preventive maintenance system
I believe that Reliability Centered Maintenance is the best approach developing maintenance tactics for critical machines. But not every plant can afford, can get approval, or has the manpower for a Reliability Centered Maintenance program.
A machinery-centered approach looks at the machine first, and by asking a series of questions, helps you decide how to maintain the machine’s health. What tests should be done? What routine PM should be done? How can we make the overhaul/no-overhaul decision?
First Ask, What Are The Possible Failures?: To ask what the failures are, first we need to know what the machine is supposed to do. What is its primary function?
Once you’ve decided what the machine’s function is, ask what can happen to prevent it from meeting that function. At this point, you’re just brainstorming. Don’t consider whether the failure is likely or has much impact. We’ll do that in the next step. For now, just get a complete list.
Next Ask, Which Of These Failures Are Significant?: Now that you have a list of possible failures, you want to decide which ones you should worry about. Some failures are so unlikely that you won’t worry about them; others have such a low consequence that their impact and cost is minor.
Machinery history is the best way to determine how often a failure occurs and what its impact is. You do have one, don’t you?
Next Ask, How Can We Avoid These Failures?: Starting at the top of the list, ask “how can we avoid this failure?” Is there some action we can take that will keep the failure from occurring? Can we change the design? Can we replace a part that has a predictable wear-out period? Can we adjust or lubricate to avoid failure? The list you make here should be the start of your preventive maintenance list for that machine.
Then Ask, When We Can’t Avoid Failure, How Can We Get An Early Warning?: There will be some failures that we can’t avoid. For those, we ask “How can we detect the failure before it occurs?” What are the symptoms of the failure? Most failures show symptoms before they happen.
Then, Tailor A Suite Of Tests To Detect Those Early Warning Signs: With a list of symptoms, you’re now in the position to select tests that measure or detect that symptom. For each symptom, try to get as many independent tests as possible.
Finally, Collect The Results Of The Tests At One Decision Point: Doing the tests without putting all the information together is not effective. I recommend that each machine have one or two individuals assigned to monitor its health. They should be trained in assessing all the information provided by the tests.
They should receive the results of the tests along with any other pertinent information on a regular basis. Then they can use that information to manage the machine.
Key takeaways:
- An average craftsperson can develop a good maintenance package for a machine.
- A simple step-by-step procedure works to define the maintenance.
- Don’t try to do the whole plant at one time, just start with the bad actors.
What methods have you used to develop maintenance packages?
Download our paper "6 Steps to a Healthy Machine"
6 Steps to a Healthy Machine