Failure modes and effects analysis (FMEA) is a core tool for reducing automotive and aerospace manufacturing risks. And yet, companies routinely waste 80% of the potential value of the FMEA process.
Particularly for manufacturers on the lower end of the maturity spectrum, FMEAs are simply a theoretical exercise for maintaining a certification or meeting customer requirements. These manufacturers may fill out an FMEA and even add a few countermeasures, but ultimately it’s just another form to file away and forget about.
The problem with this approach? Lack of closed-loop processes around FMEAs means losing crucial opportunities to prevent avoidable complaints and quality costs. Achieving meaningful value from FMEAs requires an iterative strategy, refining the model at each step and applying lessons learned to reduce defects across the board.
An FMEA is a chart used to identify, quantify and reduce risks at the design phase, comprising two of 18 production part approval process (PPAP) elements. The most common types of FMEAs focus on design of products (DFMEA) and process design (PFMEA).
The basic steps required to create a FMEA are:
- Brainstorming all the potential ways a product or process could fail
- Determining the possible consequences for each type of failure
- Assigning a rating to severity (S), likelihood of occurrence (O) and detection capabilities (D)
- Multiplying S x O x D to calculate the risk priority number (RPN) for each potential failure
- Determining which risks need additional countermeasures based on RPN
Typically, an RPN greater than 50 indicates an issue needing attention, with scores greater than 100 requiring an improvement plan (depending on internal policy). For many companies, the steps outlined above represent the entire FMEA process. But as we discuss below, creating an FMEA is just the beginning.
An Iterative Approach to FMEA
The ideal FMEA process starts at the advanced product quality planning (APQP) phase, identifying the elements that are critical to quality (CTQ) for the customer. Once the initial FMEA is complete, companies should look for opportunities to update the document during:
- Product and process design
- First article inspection
- Mass production
- Defects and complaints
Necessary adjustments may include identifying new failure modes, or updating severity, occurrence and detection data for a more accurate RPN calculation.
Ideally, you would continuously refine your FMEAs to near perfection, gaining a holistic view of risk that makes it easier to predict and prevent problems. Companies can also use those “perfected” FMEAs as a mature starting point for subsequent versions of the product, or a different product using similar processes or materials. This process involves more upfront effort, but the work required decreases over time—and delivers more consistent results.
Using FMEAs on the Plant Floor
Now that we’ve given an overview of how to refine FMEAs, let’s look at how, specifically, you should be using them on the shop floor. When a product or process breaks down, a proactive organization will use the FMEA as a problem-solving tool, asking questions like:
- Are there new failure modes we need to add?
- Where did existing countermeasures fail?
- How did the problem escape detection?
- What’s the reaction plan moving forward?
- Does the product or process need additional countermeasures?
- Do we need to update our calculations and possibly reprioritize this risk?
- Can we apply this lesson to preventive action for similar product lines and other customers?
Manufacturers can also test their FMEAs by having operators purposely create certain defects, then analyzing how long it takes to detect the problem down the line. Again, the point is to view the FMEA as a living document that you’re constantly revisiting to ensure you identify and correct any gaps.
Closing the Loop with Process Audits
Like any robust quality process, FMEAs require ongoing verification to ensure the risks you identify actually get the attention they deserve. Organizations need to verify that:
- Countermeasures are working
- Lessons learned are helping reduce risk for all customers
- All CTQ elements are consistently addressed
- Operators are implementing process changes
Process audits are a highly effective way to verify FMEAs, particularly layered process audits (LPAs) conducted at a high frequency by all levels of personnel. By checking that operators adhere to standardized processes every single shift, manufacturers can close the loop on changes initiated via the FMEA process.
Completing a high volume of audits can be a challenge for quality departments already strained for resources, particularly when using spreadsheets and traditional checklists. Manufacturers have found an automated LPA platform can deliver results faster, allowing teams to easily update questions based on FMEAs, get real-time data and boost audit compliance.
There’s no question that building an FMEA process from the ground up takes significant time and effort. But with the right attitude and tools, that investment will have a multiplier effect in terms of driving down defects, risk and costs.