People have emailed me asking why there will be a large increase in time required to create DFMEAs when the transition period from the AIAG 4th Edition FMEA Manual to the AIAG VDA FMEA Handbook ends.  The reason for this is how the existing VDA software and new AIAG CTS (assuming it supports the handbook methodology) which is driving the AIAG VDA FMEA Handbook DFMEA methodology functions:

The DFMEA methodology contained in the AIAG 4th Edition FMEA manual allows you to state that the product failed because a component was improperly specified.  As an example, if there was a potential for water intrusion, currently your AIAG 4th Edition Product DFMEA would state:

Product DFMEA (AIAG 4th Edition)

1.       Function: Prevent water intrusion.

2.       Failure Mode: Water intrusion.

3.       Failure Cause: Seal dimensions are improperly specified.

Under the new AIAG VDA FMEA Handbook DFMEA method you will not be allowed to link an improper component specification to a product failure directly.  You will be required to create a minimum of two DFMEAs, one for the product and one for the seal (Note: If the seal is part of a subassembly a DFMEA will have to be created for the subassembly as well):

Product DFMEA (AIAG VDA FMEA Handbook):

1.       Function: Prevent water intrusion.

2.       Failure Mode: Water intrusion.

3.       Failure Cause: Seal did not seal out water.

Seal DFMEA (AIAG VDA FMEA Handbook):

1.       Function: Seal out water.

2.       Failure Mode: Seal did not seal out water.

3.       Failure Cause: Seal dimensions are improperly specified.

Consequently, rather than having one DFMEA for a product, you will have a DFMEA for the product and an additional DFMEA for every subassembly and component covered by the DFMEA.  If your product has 30 components, you will have a minimum of 30 DFMEAs (more if your components combine to form subassemblies).

People have emailed me asking why there will be a large increase in time required to create PFMEAs when the transition period from the AIAG 4th Edition FMEA Manual to the AIAG VDA FMEA Handbook ends.  The reason for this is how the existing VDA software and new AIAG CTS (assuming it supports the handbook methodology) which is driving the AIAG VDA FMEA Handbook PFMEA methodology functions:

The PFMEA methodology contained in the AIAG 4th Edition FMEA manual allows you to directly identify a objectionable condition  of materials, machines, measurement, methods, people and/or environment that can cause the process Failure Mode to occur.  Currently a Seal Manufacture PFMEA constructed using the AIAG 4th Edition PFMEA method would state:

Seal Manufacture PFMEA (AIAG 4th Edition)

1.     Mold seal.

2.     Failure Mode: Seal dimensions are incorrect.

3.     Failure Cause: Contamination buildup in mold.

4.     Prevention Control: Scheduled mold cleaning.

Under the new AIAG VDA FMEA Handbook PFMEA method you will not be allowed to link an objectionable process condition to the process action Failure Mode directly.  The existing VDA software and AIAG CTS will build the PFMEA using Structure, Function and Failure Trees.  To enter the failure cause of “Contamination buildup in the mold” in our example, you will first be required to identify the material, machine, measurement, method, people or environmental element that can lead to the Failure Mode.  In our example, since the contamination buildup occurs on the mold we would define the “Mold” as the machine element causing the failure.  This would be placed in the Structure Tree.

In order to populate the Function Tree, you are next required to define the function of the material, machine, measurement, method, people or environment element that if not met would result in the Process Failure Mode occurring.  In the example provided, the function of the machine “Mold” would be to “Form mold compound to specified dimensions”.  This would be placed in the Function Tree.  

The next step will to define how the machine “Mold” can fail to meet its function.  In our case, a failure will be “Mold forms compound to incorrect dimensions”.  This becomes the failure cause of the Process FMEA.

Seal Manufacture PFMEA (AIAG VDA FMEA Handbook)

1.     Mold seal.

2.     Failure Mode: Seal dimensions are incorrect.

3.     Failure Cause: Mold forms compound to incorrect dimensions.

4.     Prevention Control: ?.

Unfortunately, the Failure Cause entered is not a root cause.  One has to ask “Why the Mold did not form the compound to the specified dimensions” until a root cause is achieved.  One root cause is the “Contamination buildup in the mold” which we were allowed to directly entered using the AIAG 4th Edition PFMEA method.  Without knowing the root cause of the Process Failure Mode, it is impossible to identify the Prevention Control required to prevent the cause and the Process Failure Mode from happening.

When using the AIAG-VDA FMEA Handbook PFMEA method, the person performing the PFMEA is faced with a dilemma.  Do they properly populate the Failure Tree and create a PFMEA with non-root causes in the Failure Cause Column or create a Failure Tree with Process FMEA Failure Cause entries that are root causes but do not describe how the item can fail to meet the Function in the Function Tree.  The creators of the proposed AIAG-VDA FMEA Handbook recognized this problem since they provided different instructions when describing how to populate PFMEA Failure Cause related entries in the Failure Tree versus how to make the same entries in the Process FMEA that the Failure Tree is supposed to create. 

With the current VDA software and AIAG CTS it is impossible to populate both the Failure Tree and PFMEA correctly. The only solution is to make major changes to existing VDA software and the AIAG CTS.  Unfortunately for the automotive suppliers, this obviously is not an option due to the cost and time involved.

Following is a link to the negative impact existing VDA software has had on the AIAG VDA FMEA Handbook:

https://www.harpcosystems.com/articles/analysis-of-negative-impacts-of-software-based-vda-fmea-methodology

It is true that Excel currently is a common software for FMEA in automotive suppliers. However, it lacks of neccesary functions to quickly create FMEA documents, as relational structure, document links,... But change to an FMEA software could cost a lot of money and time to training. So there is a simple solution (FMEA Analysis), it is an Add-In to add more functions to Excel so Excel can handle relational structure documents. More details at: https://fmea-analysis.com or https://www.iqasystem.com