Design Failure Mode and Effect Analysis (DFMEA)

DFMEA is a technique or one can say a procedure followed in most of the industries these days to identify various design risks which may hinder the performance or lead to the failure of a product.

The steps followed under this technique are as follows:

• Design Review and Identification of Potential Failures: Once the concept design is ready, it is reviewed by a cross functional team which includes people from various concerned departments viz. Design, Development, Quality and Marketing, in order to review the design and to find out various potential failures from each departments prospective.

• List out the Failures and Assign Severity Ranking: The cross functional team then brainstorms on the potential failures and list them. Each failure in the list is then assigned a Severity Number between zero to five, zero being the least severe and five being the most severe potential failure and hence the list is rearranged based on the severity ranking of the failures.

• Assign Occurrence & Detection Ranking: After the failures are ranked as per the severity, they are then ranked the same way i.e. between zero to five, based on the frequency of occurrence and chances of detection respectively.

• Calculating the RPN Number: RPN (Risk Priority Number) is calculated by multiplying the Severity, Occurrence and Detection rankings for each failure. Higher the RPN number for a failure, more is the risk involved. Hence more priority is given to that failure.

RPN: Severity X Occurrence X Detection

DFMEA Chart

• Planning and Implementation: As per the RPN number, an action plan is made in order to reduce/eliminate the failure causes and the same is implemented in the form of respective changes in the design.

• Final Evaluation and RPN Revision: After the changes in the Design are made, once again the values of Severity, Occurrence and Detection are assigned which should give a lower RPN number, which if achieved, confirms the desired results.

I would now conclude this page with a simple note that indeed DFMEA is a very useful technique but on the same time, the major problem with it is, its dependence on the participation of the people conducting it. Hence, it is very important for each participant to be thoroughly prepared and attentive while the session is conducted.