An FMEA (Failure Modes and Effects Analysis) is a quality improvement tool that helps focus on and understand potential process or product risks. During the course of an FMEA study, potential risks are identified and prioritized and used to develop action plans to reduce the risks associated with the product or process under study.
An FMEA should be performed by a team, NOT one individual. The team should include representatives of all of the functions impacting the product or the process under study. The best size for an FMEA team is 4 to 6 people. It’s difficult to successfully conduct an FMEA study with less than 3 people and more than 6 might bog the process down.
Conducting an FMEA involves a systematic step-by-step approach using a standardized FMEA Worksheet (form) to collect information on (product or process) components, their corresponding functions and potential failure modes. The risk level of those potential failures is then prioritized using a relative ranking scale. Action plans for unacceptable risks are developed. After action plans have been completed, risk levels are reevaluated to ensure the action taken was successful in reducing the risk to an acceptable level.
The time it takes to conduct an FMEA study depends on the scope of the study and the level of preparation done. With a well-defined and “reasonable” scope coupled with a comprehensive set of (organization-specific) customized ranking scales, a team can competed an FMEA study (up to the point of identifying action plans to be developed) in hours. Conversely, if the scope is “too” broad and if custom ranking scales have not been developed, the study may take several days.
A DFMEA (Design-FMEA) involves a study of a specific product. A PFMEA (Process-FMEA) is the study of a process that may produce products or provide a service. While the principles and strategy of a DFMEA and a PFMEA are essentially the same, the tactics used in some of the steps will differ somewhat.
A primary objective of a DFMEA is to uncover potential failures associated with the product such as those that could cause product malfunctions, a shortened product life or a safety hazard while using the product.
PFMEAs are used to uncover process problems related to the manufacture of a product or a series of products. When conducting a PFMEA, you need to think about how failures from the many process inputs or causes can affect process outputs such as product quality, processing efficiency and safety.
It is best to conduct an FMEA on a new product or process right in the preliminary design stage. Revisit the FMEA during the product prototype or process pilot phase. Then use the FMEA to evaluate potential risks associated with the final design or as-built process. And finally, revisit the FMEA whenever a product or process has been changed.
The outcome of an FMEA can only be as “good as the team.” If the team does not fully understand potential failures that may occur or corresponding effects of potential failures, related risks will not be recognized.
Similarly, if a team does not take the time to drill down into the details of a product design or process, critical risks may be overlooked.