There are seven-steps for conducting an AIAG-VDA DFMEA:
- 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 a DFMEA study.
- Steps 4 through 6 represent the “Failure Analysis and Risk Mitigation” phase of a DFMEA study.
- The third phase, Communication, is Step 7, Results Documentation
Step 1: Planning and Preparation
- The DFMEA 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 design into the system, subsystems, assemblies and component elements for DFMEAs.
- The Structure Analysis uses the boundaries set by the Scope Definition (Step 1) to identify every component of the product (design).
- 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 System of which the Focus Element is a part and finally identify all Components Elements contained within the Focus Element.
Step 3: Function Analysis
- Think of the Function Analysis step as exploring what the product 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 DFMEA.
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 product.
- 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 design.
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.