The AIAG-VDA Harmonization Project defined a seven-step process for conducting FMEAs.
- Planning and Preparation
- Structure Analysis
- Function Analysis
- Failure Analysis
- Risk Analysis
- Results Documentation
The seven-steps are summarized into three phases:
- Steps 1 through 3 represent the “System Analysis” phase of an PFMEA study.
- Steps 4 through 6 represent the “Failure Analysis and Risk Mitigation” phase of an PFMEA study.
- The third phase, Communication, is Step 7, Results Documentation
Step 1: Planning and Preparation
- The PFMEA study starts with a purposeful and careful definition of the scope.
- The management team is responsible for setting the scope of the study.
Step 2: Structure Analysis
- Structure Analysis is used to identify and breakdown the the process into its sequential steps, interfaces and logistical elements.
- The Structure Analysis uses the boundaries set by the definition of scope in Step 1 to identify each step, interface and logistical element of the process under study.
- Structure Analysis consists of three expanded columns whose purpose is to facilitate a thorough understanding of the process. Start with the Focus Element in the “middle column,” then identify the Process of which the Focus Element is a part and finally identify all Process Work Elements of the Focus Element.
Step 3: Function Analysis
- Think of the Function Analysis step as exploring what the product should be doing and what the overall process (and each of its steps) should be doing and how that functionality is facilitated.
- Using the Structure Analysis developed in Step 2, each element is analyzed separately in terms of its function(s) and corresponding requirement(s).
Step 4: Failure Analysis
- In Step 4, the concept of a “Failure Chain” is used to visualize failures as part of three links of a chain.
- The Failure Chain is comprised of the Failure Mode (FM), the corresponding Failure Effect (FE) and the Failure Cause (FC).
- A Failure Mode represents any manner in which an item (the Focus Element) could fail to meet its intended function.
- A Failure Effect is the consequence of a Failure Mode.
- A Failure Cause is an indication of why a Failure Mode could occur.
- Analyzing failures involves identifying how the Focus Elements detailed during the Structure Analysis may fail to perform intended functions documented by the Function Analysis.
- A failure mode leads to a failure effect triggered by a failure cause.
- Determining potential causes is at the heart of a PFMEA.
Step 5: Risk Analysis
- In Step 5, the Severity, Occurrence and Detection of each failure chain is evaluated
- An Action Priority Level of “High, Medium or Low,” based on S-O-D evaluations as indicated by the Action Priority Tables.
- The Action Priority Tables do not establish a “risk priority” but rather a priority level for action needed to reduce the risk of failure to function as intended.
- Every potential evaluation combination is assigned a High, Medium or Low priority according to the AP Table.
- If the AP level is High, action to improve prevention and/or detection controls (or justification on why current controls are adequate) MUST be taken.
- If Medium, action to improve prevention and/or detection controls (or justification on why current controls are adequate) SHOULD be taken.
- And if Low, action to improve prevention and/or detection controls COULD be taken.
Step 6: Optimization
- The primary objective of the Optimization step is to develop actions that reduce risk and increase customer satisfaction by improving the process.
- Most actions will likely involve lowering the likelihood of the occurrence of failure causes or improving detection controls; either approach leads to a more robust process.
Step 7: Results Documentation
- The results of each FMEA study should be fully documented.
- An FMEA study is not finished until Step 7 has been completed.