Reliability HotWire

Reliability HotWire

Issue 137, July 2012

Hot Topics

Good FMEAs, Bad FMEAs - What's the Difference?

"Good judgment comes from experience and experience comes from poor judgment." – Will Rogers

What’s your reason for doing a Failure Modes and Effects Analysis (FMEA)? Do you want to reduce the high cost of warranty and stem the loss of customers due to product defects? Do you want to prevent safety problems from causing harm or resulting in expensive lawsuits? Maybe you wish to design in safety and reliability to products or to manufacturing processes? Possibly you are mandated by your customer to perform FMEAs. There are countless reasons to use FMEAs in product development and operations. Whatever your reason, you believe FMEAs have the potential to achieve your goals … and you are right.

However, there’s a caveat, and it’s a big one. Not everyone gets uniformly great results from FMEAs. They have to be done properly, with the right preparation, the right team composition and the right procedure. In addition, they have to be done in such a way that they don’t consume excessive time and money. Done correctly, FMEAs will save money, speed up product development, increase safety, and achieve high reliability in products and processes. However, done improperly, they can waste time and not add value.

Why is there so much variation in the application of a tool that has been around for many decades? What can be done to help achieve more uniformly successful results? In other words, what are the quality characteristics of an effective FMEA, and how can these be evaluated and achieved? This article will answer these questions and more in the following sections:

The Hot Topics article in next month’s HotWire will describe the audit procedure of an actual FMEA and allow readers to practice auditing an FMEA.

Objectives of High-Quality FMEAs

Failure Mode and Effects Analysis is a method designed to:

  • Identify and fully understand potential failure modes and their causes, and the effects of failure on the system or end users, for a given product or process.
  • Assess the risk associated with the identified failure modes, effects and causes, and prioritize issues for corrective action.
  • Identify and carry out corrective actions to address the most serious concerns.

The primary objective of an FMEA is to improve the design. For System FMEAs, the objective is to improve the design of the system. For Design FMEAs, the objective is to improve the design of the subsystem or component. For Process FMEAs, the objective is to improve the design of the manufacturing process.

There are many other objectives for doing FMEAs, such as:

  • Identify and prevent safety hazards
  • Minimize loss of product performance or performance degradation
  • Improve test and verification plans (in the case of System or Design FMEAs)
  • Improve Process Control Plans (in the case of Process FMEAs)
  • Consider changes to the product design or manufacturing process
  • Identify significant product or process characteristics
  • Develop Preventive Maintenance plans for in-service machinery and equipment
  • Develop online diagnostic techniques

Quality Characteristics of Effective FMEAs

Based on evaluating thousands of FMEAs from hundreds of companies, certain mistakes are repeated over and over. By learning from these mistakes, we can set quality objectives that will assure high quality FMEAs. Directly below are the ten FMEA quality objectives:

  1. DESIGN IMPROVEMENTS The FMEA drives product design or process improvements as the primary objective.
  2. HIGH-RISK FAILURE MODES The FMEA addresses all high-risk failure modes with effective and executable action plans.
  3. DVP/CONTROL PLAN The Design Verification Plan (DVP) or the Process Control Plan (PCP) considers the failure modes from the FMEA.
  4. INTERFACES The FMEA scope includes integration and interface failure modes in both block diagram and analysis.
  5. LESSONS LEARNED The FMEA considers all major "lessons learned" (such as high warranty, campaigns, etc.) as input to failure mode identification.
  6. LEVEL OF DETAIL The FMEA provides the correct level of detail in order to get to root causes and effective actions.
  7. TIMING The FMEA is completed during the "window of opportunity" whence it can most effectively influence the product or process design.
  8. TEAM The right people are adequately trained in the procedure and participate on the FMEA team throughout the analysis.
  9. DOCUMENTATION The FMEA document is completely filled out "by the book," including "Action Taken" and final risk assessment.
  10. TIME USAGE Time spent by the FMEA team is an effective and efficient use of time with a value added result.

For more information about the 10 FMEA quality objectives, please refer to the article "Key Factors for Effective FMEAs," in Volume 6, Issue 2 of Reliability Edge: http://www.reliasoft.com/newsletter/v6i2/fmea_factors.htm

Auditing FMEAs using the Quality Objectives

The following FMEA audit procedure is excerpted from the book Effective FMEAs (John Wiley & Sons, © 2012, all rights reserved). It is a proven procedure and has helped hundreds of companies improve their FMEA process. It builds on the ten FMEA quality objectives.

The FMEA quality audit procedure is an essential part of ensuring good quality FMEAs. FMEA quality audits are in-person audits of completed (or nearly completed) FMEAs, done with the FMEA facilitator and the FMEA core team present. The audit can be done on a pre-scheduled or random basis. Someone, who is skilled and experienced with the content and quality of good FMEAs, performs the audit, from either management or an FMEA subject matter expert. Here is the procedure.

Each of the ten FMEA Quality Objectives have a corresponding "How to audit" recommendation. In a nutshell, an FMEA auditor reviews the FMEA results with the FMEA team against each of the FMEA Quality Objectives, one by one, using the "How to audit" recommendation. Each quality objective is evaluated for how well it is achieved. This evaluation can be done on a yes/no basis or a variable evaluation, such as high, medium or low. The estimated time is one hour for this audit, about 5 minutes per FMEA Quality Objective. The results of the audit provide valuable feedback to improve future FMEAs. The focus is on improving the FMEA process, not on the person or team doing the FMEA. The auditor is looking for specific process-related issues that underlie deficiencies in achieving the quality objectives, such as lack of training, procedure, facilitation skills, standards, resources, support, etc. Action items from the FMEA quality audit should be documented and pursued to improve the overall FMEA process. Do not expect to achieve all ten FMEA quality objectives instantly. Rather, work to maintain steady improvement.

Auditing Quality Objective # 1

The FMEA drives product design or process improvements as the primary objective.

How to audit: Look at the recommended actions and observe whether or not most of them drive design improvements (in the case of a System or Design FMEA) or process improvements (in the case of a Process FMEA). Talk with the team to ensure focus was on improvements to design or process.

Auditing Quality Objective # 2

The FMEA addresses all high-risk failure modes with effective and executable action plans.

How to audit: Review high severity and high RPN issues to see if the corresponding recommended actions are adequate to reduce risk to an acceptable level. Talk with the team to ensure they are satisfied all high risk is addressed and no important concerns are left unaddressed. One way to do this is to ask the subject matter experts for their two or three biggest concerns on the project, and then to verify that these concerns are adequately addressed in the body of the FMEA.

Auditing Quality Objective # 3

The Design Verification Plan & Report (DVP&R) or the Process Control Plan (PCP) considers the failure modes from the FMEA.

How to audit: Review the recommended actions to see if there are improvements to the Design Verification Plans or procedures, or the Process Control Plans, based on risk associated with current detection controls. Talk with the team to determine if they had adequate representation from testing and if the FMEA benefited from the testing experience, and to learn whether the test regimens were improved if the current detection controls were not adequate.

Auditing Quality Objective # 4

The FMEA scope includes integration and interface failure modes in both block diagram and analysis.

How to audit: Review items, functions, failure modes and other portions of the FMEA to ensure that interface and integration issues were taken up and addressed within the scope of the FMEA. Look at the FMEA Block Diagram to verify. Talk with the team, inquiring how they ensured no interface issues were missed.

Auditing Quality Objective # 5

The FMEA considers all major "lessons learned" (such as high warranty, campaigns, etc.) as input to failure mode identification.

How to audit: Review failure modes and causes to ensure that they contain supplemental field failure data. Preferably, there is a visual way to see which failure modes are from field information and how they are addressed. Talk with the FMEA team to ensure that the FMEA benefited from field lessons learned and that high-risk issues from the field will not be repeated.

Auditing Quality Objective # 6

The FMEA provides the correct level of detail in order to get to root causes and effective actions.

How to audit: Verify that the level of detail on higher risk issues is adequate to fully understand root causes and develop effective corrective actions. Review the different columns of the FMEA to see if the overall level of detail is proper and adequate. Too much detail shows up as endless pages of FMEA material, including areas that no one on the FMEA team is concerned about; too little detail shows up as under-defined functions, failure modes, effects, causes or controls, or as areas of unaddressed concern from one or more FMEA team members. Talk with the FMEA team to determine how they addressed the level of detail and ensured all concerns were included in the scope of the FMEA project.

Auditing Quality Objective # 7

The FMEA is completed during the "window of opportunity" whence it can most effectively influence the product or process design.

How to audit: Review the timing of the FMEA project against the product development process timing gates. Verify the FMEA was started and completed in the proper time frame for ensuring maximum value.

Auditing Quality Objective # 8

The right people, adequately trained in the procedure, participate on the FMEA team throughout the analysis.

How to audit: Review the FMEA team membership roster to ensure that there was adequate representation from the various disciplines needed based on the type of FMEA and the scope of the project. Check FMEA team meeting records to ensure attendance was adequate at each meeting. Talk with the individual team members to see if their input was elicited in the decisions.

Auditing Quality Objective # 9

The FMEA document is completed "by the book," including "Action Taken" and final risk assessment.

How to audit: Look at the FMEA to see if the various columns were properly filled out and that FMEA best practice procedure was followed. Talk with the FMEA team to ensure they rigorously followed FMEA guidelines and practices.

Auditing Quality Objective # 10

Time spent by the FMEA team is an effective and efficient use of time with a value added result.

How to audit: Talk with the FMEA team to see if each member believes his time was well spent and a value added result was achieved. If any issues arise, find out why.

FMEA audits will help ensure that FMEAs are effective in achieving quality and reliability objectives in your company. It may help to see a critical analysis of an actual FMEA to understand the characteristics of good FMEAs.

In the next Hotwire Hot Topics article, an actual FMEA will be evaluated using the audit procedure described above. Readers will be encouraged to practice auditing the FMEA using the ten quality objectives. A "teaching analysis" will be provided to demonstrate how well the FMEA achieves each of the 10 quality objectives.

If you have questions or comments about this article, the subject of FMEAs, or the book Effective FMEAs, please send an email to the author at Carl.Carlson@EffectiveFMEAs.com.

About the Author

Carl S. Carlson is a consultant and instructor in the areas of FMEA, reliability program planning and other reliability engineering disciplines. He has 30 years experience in reliability testing, engineering, and management positions, and is currently supporting clients of ReliaSoft Corporation with reliability and FMEA training and consulting. His new book, Effective FMEAs, is available on Amazon.com. Information about the book and links to useful FMEA articles and aids can be found at www.effectivefmeas.com.