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FMEA (Failure Mode and Effects Analysis)

Failure Mode and Effects Analysis (FMEA) is a systematic team driven approach that identifies potential failure modes in a system, product, or manufacturing / assembly operation caused by either design or manufacturing / assembly process deficiencies. It also identifies critical or significant design or process characteristics that require special controls to prevent or detect failure modes. FMEA is a tool used to prevent problems from occurring.

History of FMEA

FMEAs have been around for a very long time. Before any documented format was developed, inventors and process experts would try to anticipate what could go wrong with a design or process before it was developed or tried. The trial and error and learning from each failure was both costly and time consuming. For example: Each individual iteration of an invention might fail without a thorough thought experiment by a group of engineers or inventors and take advantage of their collective knowledge to reduce the likelihood of failure.

FMEAs were formally introduced in the late 1940’s with the introduction of the military standard 1629. Used for Aerospace / rocket development, the FMEA and the more detailed Failure Mode and Effects Criticality Analysis (FMECA) were helpful in avoiding errors on small sample sizes of costly rocket technology.

The primary push for failure prevention came during the 1960’s while developing the technology for placing a man on the moon. Ford Motor Company introduced FMEA to automotive in the late 1970’s for safety and regulatory consideration after the disastrous "Pinto" affair. Ford Motor Company also used FMEAs effectively for production improvement as well as design improvement.

The current advancement of FMEA has come from the automotive sector as FMEA’s are required for all Designs and Processes to assure the prevention of problems. Integrated into Advanced Product Quality Planning (APQP), FMEA in both Design and Process formats provide the primary risk mitigation tools in the prevention strategy. Each potential cause must be considered for its’ effect on the product or process and based on the risk, actions determined and risks revisited after actions are complete. Toyota has taken this one step further with its’ Design Review Based on Failure Modes (DRBFM) approach. DRBFM moves the user through the FMEA process by considering all intentional and incidental changes and their effects on the performance of a product or process. These changes drive potential causes which require follow-up action to resolve the risk. Design reviews are the primary place to review progress and address these risks.

Robustness analysis from Interface Matrices, Boundary Diagrams and Parameter Diagrams are extremely helpful prior to FMEA development. Noise factors and interfaces with other parts and/or systems are where a large number of failures can be found as design engineers typically focus on what they control directly. Shared interfaces are an area where many failures occur today.

FMEA Development

FMEAs are developed in three distinct phases where actions can be determined. It is also imperative to do pre-work ahead of the FMEA to assure that the Robustness and past history are included in your analysis.

• Step 1 is to determine all failure modes based on the functional requirements and their effects. If the severity of the effect is a 9 or 10 (meaning safety or regulatory in nature) actions are considered to change the design or process by eliminating the Failure Mode if possible or protecting the customer from the effect.
• Step 2 adds causes and Occurrences to each Failure Mode. This is the detailed development section of the FMEA process. Reviewing the probability or occurrence number in order of the highest severity and working downwards, actions are determined if the occurrence is high (> 4 for non safety and regardless of occurrence >1 when the severity is 9 or 10)
• Step 3 considers testing, design verification and inspection methods. Each combination from steps 1 and 2 which are considered at risk requires the detection number to be selected. The detection number represents the ability of planned tests and inspections at removing defects or excite failure modes to fail.

After each of these steps actions are developed. Next, Risk Priority Numbers (RPN) are calculated. Please note that RPNs are calculated after three possible action opportunities have occurred. Actions are not only determined based on RPN values. RPN threshold values do not play an important role in action development, only in action evaluation when completed.

Selecting an arbitrary RPN to fall below is both ineffective at driving change and foolhardy if the order of the improvement is not controlled (severity, occurrence, detection) steps 1.2,3 as described above.

In past years, setting an RPN would immediately be met with lower numbers without any real change or improvement. This is not preventing failure, but in fact driving bad behavior of the design and process teams required to perform the FMEA.

FMEA Exercise

Can you determine the order of need for change in the following three examples:

• Severity (5), Occurrence (4), Detection (2) = 40
• Severity (9), Occurrence (2), Detection (2) = 36
• Severity (8), Occurrence (1), Detection (8) = 64

The correct order for action is #2, #1, #3. To find out why, please contact us or sign up for our value driven training on FMEA.

FMEA in selecting Special Characteristics

FMEAs are used to refine special characteristics that the design community may be concerned about as these characteristics may affect performance. These characteristics are translated into dimensions or features and provided for the Process design activity to error proof and/or develop mitigation plans to reduce risk of poor performance. The timing for this is critical to get the best benefit. Advanced Product Quality Planning (APQP) provides the concurrent and collaborative structure to accomplish this effectively. Eventually, process capability and evidence of proper Process Controls found in a control plan are required.

FMEA use in Medical

Failure Mode and Effects Analysis is being deployed in many more industries than just Automotive and Aerospace. Medical device and drug delivery has added FMEA as a means to understand the risks not considered by individual design and process personnel. FMEA allows a team of persons to review the design at key points in product development and make comments and changes to the design of the product or process well in advance of actually experiencing the failure. The Food and Drug Administration (FDA) has recognized FMEA as a design verification method for Drugs and Medical Devices. (21 CFR §820) and typically wishes to review the effort put into the FMEA activity during scheduled reviews.

Hospitals also have begun to use FMEA to prevent the possibility of process errors and mistakes leading to incorrect surgery or medication administration. This use is driven from the Joint Commission of Accreditation of Health Care Organizations (JCAHO).

QAI has many years of experience with process driven FMEA and has trained and facilitated FMEAs for Medical Device design, drug delivery systems and hospitals wishing to prevent failure in its’ processes. Contact us to see how we could help you as well.

FMEA in Machinery Development

The reliability and maintenance of machinery is critical to many manufacturers as down time for maintenance or repair must be kept to an absolute minimum. FMEA is a tool which assists the designers and builders of tooling and equipment to determine when to improve reliability of components and where to use common parts. All R&M activities must consider the cost of ownership or total Life Cycle Costs (LCC) which must be determined well in advance of building the equipment. FMEA is an integral part of this LCC determination.

QAI has trained and facilitated many machinery and equipment FMEAs to assist in lowering LCC and preventing costly down and excessive repair time.

FMEA in Aerospace and Defense

Failure Mode and Effects Analysis has always been a part of the Aerospace industry since its’ first use in rocketry. FMEA continues to be an integral part of the development of Aircraft, Missile systems, Radar, Communications, Electronics and other key interfacing technologies. New innovations in this prevention technology have increased its’ effectiveness. Technical Kickoff (TKO) combines many tools including robustness considerations into the process yielding more detailed results and leads to improved designs and processes.

QAI is firmly committed to the use and innovation of FMEAs. We are not only a major part and input into future FMEA process, we invent processes like LEAN FMEA to help our customers use the process more efficiently. We have developed faster and more thorough techniques which provide an excellent FMEA output, while achieving the superior output faster. Please contact us to find out how we can make your FMEA experiences more valuable.

Free FMEA Downloads

QAI has a selection of FREE FMEA reference cards available for download. Now available are reference cards explaining Design FMEA and Process FMEA methodology as well as reference cards explaining the different severity, detection, and occurrence rankings. Click on a link below to begin your free download:

• Design FMEA Methodology reference card
• Design FMEA reference card
• Process FMEA Methodology reference card
• Process FMEA reference card
• FMEA for Health Care reference card

FMEA Computer Based Training

We now offer an electronic version of our FMEA training course. This course is offered on the World Wide Web for the low price of $89.00 USD. The FMEA course is Web-Based, which allows users to access their course(s) anywhere that has an internet connection, anytime. Click here to learn more about QAI's FMEA Computer Based Training course.

If you are interested in obtaining a corporate-wide license for multiple users, click here for FMEA Computer-Based Training enterprise ordering information

Check out our FREE Criteria for a Successful FMEA Presentation

Are you interested in learning more about the FMEA process? Be sure to check out our newest FMEA presentation entitled Criteria for a Successful FMEA. This short course introduces the different columns of an FMEA and shows students the most efficient way to complete the FMEA form. Criteria for a Successful FMEA is free for registered members only. Click here to view the Criteria for a Successful FMEA presentation.

Not a member? Click here to register as a member of the QAI website.

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