PM implementation, Step 3 - How Can We Avoid These Failures?
In the last installment, When building a PM system, decide which Failures Are Significant, we ranked a list of functional failures for our problem machine.
Now, starting at the top of that list, ask “how can we avoid this failure?” Is there some action we can take that will keep the failure from occurring?
For example, is there some failure symptom that shows up early enough that we can detect it prior to functional failure? Maybe there’s a process parameter we can use. Delta P or T across a heat exchanger or filter comes to mind. Or you might find a more technology based method, such as vibration, infrared, or lubricant analysis.
If there’s no symptom available, is there a time or unit based task that can prevent the failure. Can we replace a part that has a predictable wear-out period before it wears out? Do we need to change the lubrication cycle? Would an inspection help? Can we make adjustments to avoid failure? Do we need to test run the machine periodically to insure it’s still operable?
Can we change the design? After a machines is deployed, it’s usually hard to make changes in the design but not impossible. For example, can we replace a part with one more suited to the job? An example might be an enclosure that needs to be watertight but is only splash proof. Or how about an access port so a part change out can be done with less impact on production.
The list you make here should be the start of your preventive maintenance list for that machine.
For each potential solution, ask two questions:
1. Is it cheaper to do the task than it is to let the machine fail?
2. Does the task really improve the machines reliability?
If you can't answer each question with a yes, you’re probably better off not doing the task.
For each of the selected solutions, make a Job Plan that includes a step by step procedure, safety precautions, data, tools and materials needed, and a place to record the results of any inspections or readings.
Next time we’ll talk about putting it together so we get a complete picture of the machines health.
Key Takeaways:
- Detecting symptoms of failure should be the first choice for avoiding failure
- Time directed tasks may work when there is no symptom
- Don’t forget to consider design changes.
What kind of tests or tasks have you used to avoid failure?
Read all the blogs in this series:
0. 6 steps - How to develop a preventive maintenance system
1. Developing a Preventive Maintenance System - Step 1
2. When building a PM system, decide which Failures Are Significant
3. How Can We Avoid These Failures? (this post)
4. When We Can’t Avoid Failure, How Can We Get an Early Warning (coming soon)
5. Tailor A Suite Of Tests To Detect Those Early Warning Signs Warning (coming soon)
6. Collect the Results of the Tests at One Decision Point (coming soon)
Download our paper "6 Steps to a Healthy Machine"
6 Steps to a Healthy Machine