What You Need to Know About Failure Mode and Effects Analysis (FMEA)

Every product or process has modes of failure.  The effects represent the impact of the failures.  An FMEA is a tool to:

• Identify the relative risks designed into a product or process.
• Initiate action to reduce those risks with the highest potential impact.
• Track the results of the action plan in terms of risk reduction.

FMEAs help us focus on and understand the impact of potential process or product risks.  A systematic methodology is used to rate the risks relative to each other.  An RPN or Risk Priority Number is calculated for each failure mode and its resulting effect(s).  The RPN is a function of three factors:  The Severity of the effect, the frequency of Occurrence of the cause of the failure, and the ability to detect (or prevent) the failure or effect. 

• RPN = Severity rating X Occurrence rating X Detection rating
• The RPN can range from a low of 1 to a high of 1,000

Once the RPNs are determined, you need to develop an Action Plan to reduce the risks of failure modes of unacceptably high RPNs.  Next, use the FMEA as the basis for developing a Control Plan.  Control Plans are a summary of defect prevention and reactive detection techniques.

FMEA Resources

• The Purpose of an FMEA
• DFMEA or PFMEA?
• The FMEA Process
• Assembling an FMEA Team
• Design FMEA Scope
• 10 Steps to Conduct a DFMEA
• Linking DFMEAs and Control Plans
• Getting More Out of DFMEAs
• Process FMEA Scope
• 10 Steps to Conduct a PFMEA
• Linking PFMEAs and Control Plans
• Getting More Out of PFMEAs
• FMEA Limitations and Pitfalls

FMEA Checklists and Forms

Many of these forms can be downloaded as Excel Spreadsheets or Word Docs

FMEA Forms

• FMEA Team Start-Up Worksheet
• Design FMEA Scope Worksheet
• Process FMEA Scope Worksheet
• Generic Severity Rating Scale
• Generic Occurrence Rating Scale
• Generic Detection Ranking Scale
• FMEA Analysis Worksheet - Part 1
• FMEA Analysis Worksheet - Part 2

Click here to read our Newsletter that focuses on FMEAs.

Tips to Make FMEAs More Effective

Customize the rating scales

While industry guidelines suggest customizing generic ranking scales, they do not require it. However, by taking the time to add organization-specific examples of applications of the ranking definitions, FMEA teams will have an easier time applying the scales. The use of meaningful, relevant examples saves teams time and improves consistency of rankings from team to team.

Use the same (custom) ranking scales throughout the organization

Once a custom set of ranking Scales are developed, use them for every FMEA study conducted in the organization. By using the same scales, the RPN for every failure mode and effect can be compared on a relative level and the highest potential risks for the organization can identified.

Add a Control Plan right to the FMEA Worksheet

Control Plans ensure a system is in place to control the risks of the same failure modes identified in the FMEA. While Control Plans can be developed independently of FMEAs, it is time- and cost-effective to link Control Plans directly to FMEAs. The Control Plan describes how each potential failure mode will be controlled and how it should be reacted to if it (the failure mode) does occur. To add a control plan component to an FMEA, add “columns” to the FMEA Worksheet for the control factors, the specifications and tolerances, the measurement system, sample size, sample frequency, the control method, and the reaction plan.

Use a team approach

A team will be able to generate a more comprehensive list of potential failures than any one individual could do. A team approach will lead to a richer and more accurate analysis of the risks associated with a process or design.

Books and Training on FMEA

The FMEA Reference Guide   A basic guide that covers the FMEA Process - Step-by-step.  Only $9.95 each or $7.95 each when purchased in 5 packs. 

FMEA Investigator   Comprehensive online training on design and process FMEAs following AIAG/QS-9000 standards.  Available on-line or in CD-ROM or Network versions.  Click here for more information.  Click here to try a sample lesson.

FMEA Investigator for the Services/Office   The same great training as you get with FMEA Investigator, but the examples are related to office and service types of transactions rather than manufacturing of product.  Available on-line or in CD-ROM or Network versions.  Click here for more information.  Click here to try a sample lesson.

The Basics of FMEA   For years consistently in the top 10,000 at Amazon.com this book provides a simple and straightforward overview of FMEAs.  Click here for more information.

Links

FindArticles:  A great resource for articles on FMEAs in a number of different industries..

FMEA Info Centre:  According to the site:  The FMEA Info Centre is a non-commercial web-based inventory dedicated to the promotion of Failure Mode and Effect Analysis.

FMEA Articles from ISixSigma:  Access to several different articles on FMEA in different industries.