Today's organizations face unprecedented worldwide competition as a result of three continuing challenges: the mandate to reduce costs, faster development times and high customer expectations for the reliability of products and processes. The necessity for reliability assurance will not abate; however, there is increasing emphasis on Design for Reliability as an organizational strategy.
One of the tools that show up on almost every "short list" of Design for Reliability tools is Failure Mode & Effects Analysis. Most corporate and military applications require some form of FMEA or FMECA. Yet questions remain about the overall effectiveness of FMEA as applied in many companies and organizations today. Frankly, there are mixed results with FMEA applications.
The prerequisite for effective FMEAs is a sound knowledge of the basics of FMEA. There is no substitute for learning these fundamentals. Interested readers are encouraged to take ReliaSoft’s two day training course that covers the FMEA basics and supporting software (RS 470: Failure Modes Effects and Criticality Analysis and Xfmea). Once these basics are well understood, it is possible to capture and apply certain lessons learned that make FMEAs highly effective.
There are a number of success factors that are critical to uniformity of success in the application of FMEA in any company. In the previous issue of Reliability Edge, the focus was on an effective FMEA process. This article will outline the lessons learned and quality objectives that make for effective FMEAs.
The FMEA lessons learned presented here are the result of personally supervising or participating in over a thousand FMEA projects, and collaboration with many corporations and organizations on the FMEA process and its shortcomings.
There is a maxim that says, "Good judgment comes from experience and experience comes from poor judgment." Based on this maxim, the following lessons learned are based on considerable experience. Each of these lessons is from direct experience of how FMEAs were done wrong and how to improve the overall effectiveness.
FMEA Lessons Learned
Mistake # 1
Failure of the FMEA to drive design or process improvements
Quality Objective # 1
Note: Reliability Engineering has a multitude of tools to choose from in driving design or process improvements. The key is to use the FMEA "Recommended Actions" field to identify and execute best practice tools that can optimize designs. This is one of the reasons that Reliability Engineers need to participate on FMEAs.
Mistake # 2
Failure of the FMEA to address all high-risk failure modes
Quality Objective # 2
Note: The emphasis on this Quality Objective is to ensure that all of the high-risk failure mode/causes are adequately addressed with effective actions. The key is effective action that reduces or eliminates the risk.
Mistake # 3
Failure of the FMEA to improve test/control plans
Quality Objective # 3
Note: The FMEA team will often discover failure modes/causes that were not part of the design controls or test procedures. The key is to ensure that the test plan (DVP&R) or Control Plan is impacted by the results of the FMEA. This can be done by including test/control membership on the FMEA team or through well-written actions.
Mistake # 4
Not including interfaces or integration in FMEA
Quality Objective # 4
Note: Interfaces can be included as part of the item by item analysis or as a separate analysis. It is recommended that the FMEA Block Diagram clearly show the interfaces that are part of the FMEA scope.
Mistake # 5
Disconnect between FMEA and information from the field
Quality Objective # 5
Note: Field failure data can be brought into generic FMEAs on a regular basis. Then, when new program-specific FMEAs are started, they benefit from field lessons learned. If generic FMEAs are not used, new FMEAs should be seeded with potential field problems and required to show how they will not repeat in the new design/process. The key is to hold the FMEA team responsible to ensure that major field problems do not repeat.
Mistake # 6
FMEA omits Key Characteristics
Quality Objective # 6
Note: This is an underutilized element of FMEAs. Both the SAE J1739 and AIAG FMEA-3 guidelines for FMEA use the "Classification" column.
Mistake # 7
Doing FMEAs late
Quality Objective # 7
Note: The key to getting FMEAs done on time is to start the FMEAs on time. FMEAs should be started as soon as the design or process concept has been determined. The exception is FMEAs done during trade-off studies, which should, of course, be started earlier.
Mistake # 8
FMEAs with inadequate team composition
Quality Objective # 8
Note: Based on an actual survey of Reliability Engineering internal customers on FMEAs: FMEAs are too important not to do, but too time consuming to participate in. The FMEA facilitator must value the time of team members and not waste time. People have blind spots (scotomas). The key is to get the people who are knowledgeable and experienced about potential failures and their resolutions to actually show up at the meetings. Attendance often takes management support. Team size is best between four to eight people. If the team gets too large, consider breaking into additional limited-scope FMEAs.
Mistake # 9
FMEAs with improper procedure
Quality Objective # 9
Note: One common problem is the failure to get to root cause. Expert input is necessary. Follow-up actions based on poorly defined causes will not work and the FMEA will not be successful. Another common problem is lack of follow-up to ensure that the FMEA Recommended Actions are executed and the resulting risk is reduced to an acceptable level.
Mistake # 10
Lack of efficient use of time
Quality Objective # 10
Note: If this Quality Objective is met, then future FMEAs will be well attended and supported by subject matter experts and management.
In-person audits of completed (or nearly completed) FMEAs should be done. They are performed by supervisors and managers over the FMEA process, with the FMEA facilitator and core team. An in-person interview format is recommended, on a pre-scheduled or random basis. Typically they take one hour maximum per audit, which amounts to about five minutes for each of the ten FMEA Quality Objectives.
FMEA audits provide valuable feedback to improve future FMEAs, in the form of action items identified for follow up. Focus needs to be on improving the FMEA process, not on the person/team doing the FMEA. Don't expect to instantly achieve all ten objectives; work to maintain steady improvement. Management audits demonstrate commitment. In the words of W. Edwards Deming, "Quality cannot be delegated."
Achieve the FMEA Quality Objectives and your result will be more effective FMEAs for your company or organization.
ReliaSoft Training Course: RS 470 - Failure Modes, Effects and Criticality Analysis. On the Web at http://www.ReliaSoft.com/seminars/gencourses/rs470.htm.
Society of Automotive Engineers, SAE J1739: Potential Failure Mode and Effects Analysis in Design (Design FMEA), Potential Failure Modes and Effects Analysis in Manufacturing and Assembly Processes (Process FMEA), and Potential Failure Mode and Effects Analysis for Machinery (Machinery FMEA). SAE International, Warrendale, PA, June, 2000.
NOTE: The author participated in the development of the SAE J1739 guidelines for Design, Process and Machinery FMEAs. The Quality Objectives presented in this article are also reflected in Appendix A and Appendix B of that document, which is available for purchase from the Society of Automotive Engineers (http://www.sae.org).