Failure Mode and Effects Analysis

The FMEA analysis is normally conducted by a cross-functional team. A team of subject matter experts is a critical element of FMEA success.

The FMEA is a widely accepted methodology across many industries. There are several standards that provide guidance on how to determine the FMEA scoring for different types of FMEAs.

There are many types of failures. When conducting an FMEA, all failure types must be considered, not just the most obvious. Each category of failure should be considered for every product component or process step.

The FMECA is a special form of FMEA that accentuates the focus on finding and controlling critical characteristics. It simplifies the FMEA process, but loses fidelity in the analysis.

Critical characteristics drive cost and complexity in process operations. Design FMEAs identify critical characteristics. Process FMEAs assess the ability of the organization to control critical characteristics.

The first three steps of the Design FMEA process set the stage for effective FMEA analysis sessions. Cutting corners on these steps lead to confusion and delays in the analysis.

The final four steps of the Design FMEA are where the assessment happens. These steps do the original analysis and manage the mitigation of high risk failures.

Failures are based upon the product or system's functional design The functional block diagram of the system or product initiates the FMEA analysis.

Each of the functions identified in the block diagram are susceptible to failures. These failures are identified and recorded on the FMEA.

An effect on the customer or user is determined for each failure mode and listed in the Design FMEA. The severity of that effect is rated to determine the impact.

Causes for each failure in the Design FMEA are identified. The probability of each of those causes occurring is evaluated and scored.

The product design and development process is evaluated to determine if it is able to detect each of the failures listed in the Design FMEA. This detection capability is evaluated and scored.

The first three steps of the Process FMEA process set the stage for effective FMEA analysis sessions. Cutting corners on these steps lead to confusion and delays in the analysis.

The final four steps of the Process FMEA are where the assessment happens. These steps do the original analysis and manage the mitigation of high risk failures.

Failures are based upon the process steps. A process map identifies all the steps in the process. These steps initiate the Process FMEA.

Each of the steps identified in the process map are susceptible to failures. These failures are identified and recorded on the FMEA.

An effect on process performance or operator safety is determined for each failure mode and listed in the Process FMEA. The severity of that effect is rated to determine the impact.

Causes for each failure in the Process FMEA are identified. The probability of each of those causes occurring is evaluated and scored.

The process is first assessed to determine if the failure modes identified in the Process FMEA have been prevented based upon the process design or management. The process control plan is then evaluated to determine if it is able to detect each of the failures listed in the Process FMEA. This prevention and detection capability is evaluated and scored.

The severity, occurrence, and detection ratings are combined to create a Risk Priority Number (RPN). When that RPN exceeds the organization's risk threshold for Process FMEAs, a mitigation strategy is developed and implemented to lower the scores until the RPN is acceptable.