We’re jumping into an FMEA starting to populate table cells and organize information. We may even be doing things right, having a team approach and inviting our cross-functional team members to the discussions. We get started, but then we don’t agree on ratings to assign, like severity, occurrence, or detection ratings. Or we get anywhere from 50% of it done to getting it all filled in and then we don’t know what to do with it. We can avoid these headaches with a little planning (or maybe a lot of planning, it depends). Let’s talk risk management planning as it pertains to using FMEA after this brief introduction.
Hello and welcome to Quality during Design, the place to use quality thinking to create products, others, love for less. My name is Dianna. I’m a senior-level quality professional and engineer with over 20 years of experience in manufacturing and design. Listen in and then join the conversation qualityduringdesign.com.
Failure mode effects analysis, FMEA is an analysis tool about the failure modes and the effects that it can have on our product performance, safety, and dependability. It’s proactively thinking about how things could go wrong, so we think in terms of potential: potential failures, potential effects, and potential causes. We can use FMEA to evaluate those effects on different aspects of our product design. We can evaluate the failure modes and their effects to our system, performance, component design, functionality, user process or the manufacturing production process. Most often, we’ll use different FMEA to evaluate these different aspects of our product design.
The idea is to analyze how things can go wrong, why they could go wrong and then either prevent them from happening or be able to detect it before it happens. When we’re all done with the revision zero of an FMEA, what do we get out of it?
- we get a list of potential failure modes and their causes (their root causes)
- the list of potential hazards or effects (associated with whatever analyzing)
- a ranking of how severe our failure mode is [in creating effects]
- a ranking of how often we think the failure mode will occur because of a certain cause
- a ranking of how easy it is for us to detect the cause of the failure mode before bad things happen.
All of this information can be used to help drive design decisions. It sounds like a wonder analysis, and it can be! At the top of this podcast, we talked about getting into an FMEA and then not knowing what to do with it. That’s because we need to plan how we’re going to use the FMEA for design choices.
What our plans should include
We can think of FMEA like a design test. It’s a thought experiment, after all, where we’re initially thinking about all the potential ways our product can fail and the potential root causes and effects of that failure. Thinking of the way we test our designs, we wouldn’t throw any old component on any test machine and just start doing stuff. We want to plan out what we’re testing, how we’re testing it, and what limits we’re testing to. We have a test plan and we have a test protocol which includes acceptance criteria that answers, “How are we going to judge if our test is successful or not?” Our FMEAs also need a plan of execution and acceptance criteria. Otherwise, we won’t know how to start it, finish it or what we’re to do with the results.
Our plan should include what types of FMEAs we’re going to perform: system, FMEA. hazard analysis, critical analysis, design FMEA, usability FMEA, and so on. We can think of the different types of FMEAs like choosing the right test equipment. We’ll also plan for what systems or components are going to have an FMEA. For example, maybe we’ll perform a system FMEA, but then only analyze critical components in a design FMEA. We might decide that not everything needs an FMEA.
We’ll plan for how we’re measuring the results by clearly describing what the rankings mean. If we have a severity of 8, what does that mean? If a failure mode has more than one effect, how will we handle that? Will we use the worst-case severity rating? We’ll define our occurrence ratings, too, and decide if we’re going to assess the occurrence of the failure due to a specific cause, or we’ll apply another method of estimating occurrence. We’ll also decide if we’re using a detection rating and assign meaning to those ratings do,
Will have acceptance criteria. Are we all right with allowing any severity that’s a 10? If an occurrence rating is above a threshold, are we going to do something about it to reduce it? Or maybe we will consider a combined Risk Index of severity and occurrence: are there any combinations that we’ll think of as unacceptable? How about a risk prioritization number limit, which is classically severity X occurrence X detection? For areas of the FMEA that don’t meet our acceptance criteria: how are we going to track action items and decisions? Are we going to use the FMEA itself or a different method?
We’ll ensure that the team contributing to the FMEA has the proper instruction to how they’re built and used. Just like, we have a test technician in the lab that knows how to operate the equipment, we want our team to know how to use an FMEA.
Finally, we’ll plan for how we’re going to document the results.
Once we have a risk management plan for FMEA that the team understands and is on board with, then we’ll have the foundation to start creating meaningful FMEAs that can be used for design decisions throughout the design process.
What’s today’s insight to action?
If you’re involved in an FMEA right now, are you familiar with its plan? Think of it like a test plan because it’s a thought experiment. Does your team have all the pieces they need to do an FMEA with purpose? Do you have ratings or rankings that help you measure results? Do you understand how to apply them to the FMEA? Do you have acceptance criteria?
Anytime you’re invited to participate in an FMEA, look up the plan first and ensure you’ll be able to contribute meaningfully to its results. And if you don’t understand the plan, ask questions before the FMEA working meeting so that you do.
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