Design Failure Mode Effects Analysis (DFMEA)
The Design Failure Mode Effects Analysis (DFMEA) process is a powerful tool in the continuous improvement arsenal. While many people are familiar with the generic FMEA, the DFMEA starts the analysis at the systemic design level. It provides a structured approach to analyze each component within the system, their interactions with other components in the system and how they fail individually and in concert.
The DFMEA process evaluates each failure mode to first identify:
The Probability- the likelihood that this failure mode will occur (on a scale of 1-10 with 10 meaning that it will occur frequently)
The Severity - the impact that this failure mode has when it occurs, is it catastrophic or transparent (on a scale of 1-10 with 10 meaning major customer impacting issues will occur)
The Detectability - the likelihood that when the failure occurs it will be proactively detected (on a scale of 1-10 with 10 meaning that it is not detectable and would rely on end users to identify and notify the appropriate teams of the issue)
the product of these three numbers is called a Risk Priority Number (RPN). While the RPN is not universally comparable, it does allow the team to focus on identifying the biggest potential risks caused by system failures.
The next step in the DFMEA is to evaluate if any changes can be made that would adjust one of the three numbers above. Even small monitoring changes can have a significantly positive impact on the RPN. These mitigating steps are fed as input into the Continuous Improvement cycle and a separate RPN is calculated based on after the improvement is implemented. This information helps prioritize what failure modes should receive improvement efforts or investment.
When applied correctly the DFMEA along with the continuous improvement cycle and 4DX provide major tools to increase stability and reliability of almost any large and complex system.