Design FMEAs

The Design FMEA (DFMEA) is a disciplined analysis of the part or service design with the intent to prevent the design-based failure modes prior to the first production run or service delivery. It needs to be done early in the product/service design cycle -- as soon as the design concept has been selected.

The DFMEA involves:

Identifying the potential or known failure modes (step 4) for the part functions (described in steps 2 and 3),

Identifying the effects (step 5) and the causes (step 6) of each failure mode,

Prioritizing the identified failure modes based on the frequency of occurrence O (step 7), the severity S of the failure mode (step 8), and the likelihood of detection D (step 9), where for each criterion 10 represents the worst-case situation and 1 represents the best-case situation,

Providing for follow-up corrective and preventive actions (step 11) on the prioritized (via the Risk Priority Number in step 10 = O x S x D) causes.


Process FMEAs

The Process FMEA (PFMEA) is a disciplined analysis of the part's/service's processes with the intent to prevent the process-based failure modes prior to the first production run or service delivery, before money is spent on equipment, systems, tooling, etc.  The focus is to prevent, or at least detect, changes in the process variables which could lead to a deviation from the design requirements.  For the PFMEA, step 2 lists the process involved in making the part/service being studied, and in step 3 there is a short description of the purpose of the process.  The other steps (and columns) of the PFMEA are very similar to those of the DFMEA.