Failure Mode, Effects and Criticality Analysis (FMECA)
Reliability Centered Maintenance (RCM)
Weibull
Accelerated Life Testing
6 Sigma
Root Cause Analysis (RCA)
All buzz words, but they all have merits. If applied together, and performed by suitably skilled personnel, they can be invaluable in asset management decision making.
How many times have you heard, after a so called in depth Reliability Centered Maintenance (RCM) analysis, "Our maintenance strategy is run to failure". It doesn't have to be this way! We have seen the above tools used, abused and discarded as they fail to produce the promised results. When key elements are used properly they provide you with the confidence your assets will perform at a known level.
Failure Mode, Effects and Criticality Analysis (FMECA) is a design document that should feedback design weak points to the design team to ensure new products have good reliability when launched. If done properly it should also minimise risks to as low as reasonably practical. Rarely are failure rates and failure modes validated for the intended application so the document usually becomes nothing more than a contract deliverable, providing minimal useful information for asset management.
RCM "run to failure" is a flawed assumption. When faced with this scenario, you need to develop performance tests to measure critical parameters of your asset. This is often not easy due to lack of expertise, test equipment, equipment physical size and asset downtime access, etc. Most electrical and electronic components are treated this way due to lack of expertise in this area. Maintenance has always been more mechanical, right?
Weibull is used to provide a level of confidence of a predicted failure rate, help identify infant mortality and wear out phases, and understand the expected product's life. Used in conjunction with the other analysis tools, Weibull can provide valuable insight into future asset performance.
Accelerated life testing, when applied correctly, can be used to validate models and provide an additional level of confidence in understanding failure modes and their characteristic life.
6 Sigma provides a statistical tool box to analyse in service failures and test data to understand the probabilities of failure and ensure test methods are repeatable and reproducible.
Root Cause Analysis (RCA) helps you identify how things fail. Ideally the findings should be fed back into the FMECA, but this rarely happens.
Sounds easy but, in reality, it's not. Companies will provide you with a Black Belt, whose primary qualifications are accounting, to solve an engineering problem. Now you'll spend all your time educating rather than benefiting! Weibull analysis requires accurate data. How often do you see parts replaced that are still fully functional due to poor diagnostics? Using data like this will seriously flaw your predictive model. FMECA documents use theoretical failure rates and modes and are often misrepresentative of real life applications. RCM takes considerable time and requires an in-depth knowledge of not only the asset function but the individual parts that make up the asset. Accelerated life testing has a fine line between shortening the test time and prematurely inducing failures.
As an engineer responsible for asset maintenance, having to attend meetings, manage staff and manage reactive management, will likely leave you with little time to work on the things that matter most, asset reliability. Why does this sound familiar? We've been there! To do this, you need a properly skilled and qualified team, a decent test facility coupled with significant statistical knowledge, otherwise you'll always be making decisions with only half the picture and your understanding and confidence in future performance will be largely unknown. At Custom Engineering Solutions, we have the skills, knowledge and engineering capability to help you solve the remainder of the predictive maintenance puzzle.
Remember machines are honest, and if you want improved asset performance you have to use the available data in the right way. Otherwise it’s just down to luck!
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