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AIAG-VDA 7-Step DFMEA Process

AIAG-VDA 7-Step FMEA Process

There are 7 steps for conducting an AIAG-VDA DFMEA:

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

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.

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).

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.

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.

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.