A DFMEA (Design Failure Mode and Effects Analysis) examines the design of a product to find where the design itself could fail, before anything is built. It works alongside the PFMEA, which analyses the process that makes the part. Together they cover the two biggest sources of quality risk: a flawed design and a flawed process.
In the systems we build for aerospace and manufacturing clients, mixing these two up is one of the most common audit findings, and a clear sign a team does not yet understand its own risk.
Key takeaways
- DFMEA analyses the design; PFMEA analyses the process.
- The DFMEA comes first and shapes the PFMEA.
- Both use Severity, Occurrence and Detection scoring.
- Special characteristics must hand off from DFMEA to PFMEA.
What is a DFMEA used for?
A DFMEA is used during design to ask how each feature or function could fail and what that would mean for the customer. It drives design verification and testing, flags the characteristics that matter most, and feeds directly into the process work that follows. It is a core output of APQP.
DFMEA vs PFMEA vs FMEA
| Type | Analyses | Owned by |
|---|---|---|
| FMEA | The general method | Any team |
| DFMEA | The product design | Design engineering |
| PFMEA | The manufacturing process | Process and quality |
See our full guide to PFMEA for the process side.
The 7 steps of a DFMEA
- Define the scope and break the design into functions.
- List failure modes for each function.
- Identify effects and rate Severity.
- Identify causes and rate Occurrence.
- Review design controls and rate Detection.
- Prioritise with Action Priority (or RPN).
- Act and re-score after design changes and verification.
How DFMEA scoring works
DFMEA uses the same Severity, Occurrence and Detection logic as a PFMEA. Severity is set by the effect and rarely moves; you cut risk by improving the design or adding stronger verification. The modern AIAG-VDA method ranks risk with an Action Priority of High, Medium or Low. The official method is published by the AIAG.
The OQS DFMEA-to-PFMEA hand-off check
The moment a DFMEA fails an audit is usually the hand-off to the process side. Before you close a DFMEA, confirm these four transfers actually happened:
- Special characteristics from the DFMEA appear in the PFMEA and control plan.
- High-severity effects are protected by a real process control, not a note.
- Design assumptions (loads, tolerances) are communicated to manufacturing.
- Open design actions are closed before production planning is finalised.
If all four transfer cleanly, your DFMEA and PFMEA will tell the same story to an auditor.
Common DFMEA mistakes we see
Three problems come up again and again. First, teams fill the DFMEA with process issues that belong in the PFMEA, which blurs ownership and weakens both documents. Second, they close the DFMEA before design verification has actually confirmed the fix works, so the score on paper looks better than the design really is. Third, they never revisit it after a design change, leaving a document that no longer matches the product. Avoiding these three keeps a DFMEA useful long after launch, and keeps it credible in front of an auditor.
DFMEA FAQ
Do I need both a DFMEA and a PFMEA? If you design and make the part, yes. If you only manufacture to a drawing, the PFMEA is usually the priority.
Which comes first? The DFMEA, because its outputs shape the process and the PFMEA.
Are FMEAs required for AS9100? AS9100 requires risk management, and under AS9145 APQP the DFMEA and PFMEA are the standard tools used to meet it.
How often should a DFMEA be updated? Whenever the design changes or a new failure is found. A DFMEA that never changes is usually one that has stopped being used.
Need FMEAs your customer will accept?
Optimal Quality Solutions helps aerospace, defense and manufacturing teams build audit-ready quality systems, with a 98% first-time certification success rate and 15+ years of hands-on experience.
