For this month I thought I’d write about the Design Failure Modes and Effects Analysis (DFMEA) and how it can be used on a project.  Methods such as the DFMEA when used during the concept phase of the project can help a design team to work better together, share experiences and identify possible problems early.  Performing a DFMEA requires the entire team to gather and review the design and identify ways it might fail in use.  It’s best if this is done with the entire design team as this allows you to bring in the experience of all the members.

While brainstorming sessions aren’t always popular, or successful, these can work for DFMEAs if the group approaches it with an open mind and willing to share.  Once the possible failures are identified then next is  identifying the potential effects of  each failure, i.e. limited operation, loss of functions, total loss.  This is where experienced team members can play an important role by providing history from other projects, while new members bring in the ability to ask “why not” to the comment that it’s been tried before.  Based on these you can assign severity levels, where 10 is the highest  (likely)and 1 is the lowest (remote).  With this complete you move to assigning the detection rankings, i.e. how easy/hard will it be to determine what has failed.  Scoring for detection is typically 10 for low/uncertain detection and 1 is high/certain of detection.

With these completed we can calculate the Risk Priority Number (RPN). This is calculated by the following:

RPN: severity x occurrence x detection.

The RPN can then be used by the design team to make design decisions (concept stage), in later stages it can be used to make the product design safer and robust , and after the product is in production it  can be used to select features for further product improvement.

As in any effort related to risk it’s all about communications, sharing experiences and identifying the best ways to implement a solution that limits risk while providing max functionality/capability.  With technology changes something that failed in the past may be viable today, openness to considering all options is essential to product success.

BIO:
Paul Kostek is a principal of Air Direct Solutions a systems engineering/project management firm located in Seattle.  He works with companies in the aerospace and medical device industries.