Types of FMEA
- Design FMEA (DFMEA) examines a product design for failure modes before it is released.
- Process FMEA (PFMEA) examines a manufacturing or service process step by step.
- System FMEA looks at interactions between subsystems.
PFMEA is the most common on the shop floor and is required in automotive (IATF 16949) and expected in medical device and aerospace quality systems.
The steps
- Define the scope and assemble a cross-functional team.
- List the process steps or functions.
- For each step, list the failure modes: the ways it could go wrong.
- Identify the effects of each failure on the customer or the next step and rate severity (S).
- Identify the causes and rate how often each occurs: occurrence (O).
- Identify current controls and rate how likely they are to catch the failure: detection (D).
- Prioritise. Traditionally S × O × D gives a risk priority number (RPN); the AIAG-VDA 2019 handbook replaced RPN with an action priority (AP) table.
- Define and take actions to reduce occurrence or improve detection, then re-rate.
Common mistakes
- Treating the FMEA as a document for the auditor rather than a living analysis.
- Rating in a meeting room without the people who run the process.
- Chasing the RPN total instead of the high-severity rows.
- Never revisiting it after a failure actually occurs.
FMEA and daily management
An FMEA is a prediction; the tier board records what actually happened. Defects, near misses and breakdowns raised daily should feed back into the FMEA, and the actions the FMEA generates belong on the same action list as everything else, with owners and dates, rather than in a spreadsheet nobody opens.