The Process Failure Mode and Effects Analysis (PFMEA) is a required element of the PPAP submission and is used to systematically identify and evaluate potential failures within the manufacturing process for the part in question.
PFMEA focuses on how the process could fail, the effects of those failures, and the controls in place to prevent or detect them. Once created, the PFMEA becomes a living document that must be reviewed and updated throughout the entire lifecycle of the part.
Purpose of PFMEA
PFMEA evaluates each step defined in the Process Flow Diagram and assesses risk by assigning numerical rankings for:
- Severity (S): The seriousness of the effect of a failure
- Occurrence (O): The likelihood of the failure occurring
- Detection (D): The likelihood that the failure will be detected before reaching the customer
These ratings—typically scored on a scale of 1 to 10—are used to calculate the Risk Priority Number (RPN) or, under newer methodologies, to determine action priority.
The goal of PFMEA is to identify high-risk process steps and drive corrective actions that reduce or eliminate risk before production issues occur.
How PFMEA is used
An effective PFMEA:
- Highlights where the production process is most vulnerable
- Drives improvements to tooling, methods, inspection, and controls
- Supports development of a robust Control Plan
- Helps teams understand root causes when failures do occur
By proactively addressing risks, PFMEA reduces defects, rework, scrap, and customer complaints.
Relationship to PPAP and Control Plan
PFMEA is directly linked to:
- The Process Flow Diagram, which defines each process step
- The Control Plan, which defines how risks are controlled in production
Any mismatch between these documents can undermine the credibility of a PPAP submission.
Key considerations
- PFMEA must reflect the actual production process
- It should be updated following process changes, defects, or customer feedback
- Actions must be clearly defined, implemented, and verified
- High-risk items should always be addressed before PPAP approval
PFMEA is one of the most powerful tools within PPAP for preventing failures rather than reacting to them.