PFMEA (Process Failure Mode and Effects Analysis) is a structured method for finding how a manufacturing process can fail, scoring how serious each failure is, and fixing the highest risks before they ever reach the customer. It is the tool that turns a vague sense of “this step feels risky” into a ranked, owned action list.
In the quality systems we build for aerospace and manufacturing clients, the PFMEA is the document auditors probe hardest, because it reveals whether risk thinking is real or just paperwork completed the week before the audit.
Key takeaways
- PFMEA analyses the process; DFMEA analyses the design.
- Every failure is scored on Severity, Occurrence and Detection.
- Modern PFMEAs use AIAG-VDA Action Priority, not a single RPN cutoff.
- A PFMEA only works if the actions are closed and it is kept live.
What is PFMEA in manufacturing?
A PFMEA examines each step of a manufacturing process and asks three questions: how could this step fail, what happens if it does, and how likely are we to catch it before it ships. Each potential failure is scored, and only the highest scores earn action. It is a core output of APQP and AS9145 and supports the risk-based thinking that AS9100 and ISO 9001 both require.
What are the 7 steps of PFMEA?
- Map the process. Break the process into steps and state the purpose of each one.
- List failure modes. For every step, describe how it could go wrong: wrong torque, missed inspection, contamination, wrong material.
- Rate Severity (S). Score how serious the effect is if it reaches the customer, 1 to 10.
- Rate Occurrence (O). Score how often the cause is likely to happen, using real data where you have it.
- Rate Detection (D). Score how likely your current controls are to catch the failure first.
- Prioritise. Use the AIAG-VDA Action Priority table (or the older RPN = S x O x D) to rank the risks.
- Act and re-score. Reduce the top risks, then re-score to confirm the action worked.
PFMEA vs FMEA vs DFMEA
FMEA is the umbrella method; PFMEA and DFMEA are the two forms you actually use.
| Type | What it analyses | Owned by |
|---|---|---|
| FMEA | The general method | Any team |
| DFMEA | The product design | Design engineering |
| PFMEA | The manufacturing process | Process and quality |
Most manufacturers need both a DFMEA and a PFMEA. We break the split down further in our guide to DFMEA vs PFMEA.
How PFMEA scoring works
Severity is fixed by the effect and rarely changes; you reduce risk by lowering Occurrence through better process control, or Detection through better checks and error-proofing. The current AIAG-VDA method replaces a single RPN threshold with an Action Priority of High, Medium or Low, which stops teams chasing an arbitrary number. The official method is published by the AIAG.
Is PFMEA a Six Sigma tool?
PFMEA is used within Six Sigma, but it did not originate there. It is a core quality-planning tool that fits into APQP, Six Sigma, and any risk-based quality system. In a DMAIC project it usually appears in the Analyse and Improve phases.
PFMEA example
Take a machining step that drills a mounting hole. The failure mode is “hole drilled undersize.” The effect is that the bracket will not assemble, so Severity might be 7. The cause is drill-bit wear, and with no monitoring the Occurrence might be 6. If the only control is a final visual check, Detection could be 7. That combination lands in a high Action Priority, so the team adds tool-life tracking and an in-process gauge, then re-scores. Occurrence and Detection drop, and the risk moves to Low.
How to build a PFMEA (and mistakes to avoid)
Run the PFMEA as a cross-functional session with process engineering, quality, and the operators who actually run the step. Use an agreed, written S/O/D scale so scores mean the same thing to everyone. The most common failures we see in audits are simple: the PFMEA is written once and never updated after a process change, scores are set by gut feel, or risks are listed but the actions are never closed. Link it to your control plan so improvements actually reach the shop floor.
The OQS PFMEA readiness check
Before any certification or customer audit, we run a client’s PFMEA through five checks that catch the issues auditors actually raise. This is the shortlist we wish every supplier used:
- Control-plan link. Every high-severity failure mode has a matching entry in the control plan, so the risk is genuinely controlled on the floor, not just noted.
- Design hand-off. Special characteristics flow in from the DFMEA, rather than being invented at the process stage.
- Evidence-based Occurrence. Occurrence scores trace to real scrap, rework or field data, not a show of hands in the meeting.
- Closed actions. Every High Action Priority item has a completed action with objective evidence, not an open promise.
- Live revision. The revision date matches the last real process or tooling change, which proves the document is actually used.
If a PFMEA passes these five, it almost always survives the audit. If it fails even one, that is usually where the finding comes from.
PFMEA FAQ
What does PFMEA stand for? Process Failure Mode and Effects Analysis.
Is there a PFMEA template? Yes, most teams use the AIAG-VDA worksheet, but the template matters far less than an honest process map and closed actions.
RPN or Action Priority? New PFMEAs should use the AIAG-VDA Action Priority tables; RPN is the older approach many legacy documents still use.
Is PFMEA required for AS9100? AS9100 requires risk management, and for aerospace product realization the PFMEA is the tool most suppliers use to meet it, especially under AS9145 APQP.
Need a PFMEA your auditor will trust?
Optimal Quality Solutions helps aerospace, defense and manufacturing teams build audit-ready FMEAs, control plans and full quality systems, with a 98% first-time certification success rate.
