Major changes in the AIAG and VDA harmonized FMEA manual

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The method of analysis of failure modes and their possible consequences, known by the acronym FMEA, has been known since the 1940s. This useful method, which helps reduce losses associated with product or process failures, has evolved over time and has penetrated sectors for which it was not originally intended. It found mass application in the automotive industry, where it became part of the project documentation and communication between the supplier and the customer.

The long-awaited change
 

Due to the dynamics of the development of customer-supplier relationships and the need for continuous process improvement, the hitherto valid 4th AIAG FMEA manual. This edition no longer met the requirements for clear and comprehensible output required by manufacturers, suppliers and customers.

This was the input for the preparation of a new comprehensive review of the FMEA, in which two major automotive associated organizations, AIAG and VDA, worked with OEMs and selected Tier 1 suppliers. Get to know at least the most important changes now.
 

RPN is leaving, AP is coming
 

Anyone who has met the FMEA knows the concept of Risk Priority Number, RPN for short. This number determined the severity of the risk analysed and identified the priority with which corrective action should be taken to avoid disagreements. The new handbook has completely given up this parameter and it must be said that this is the right step. Anyone who has ever worked for an FMEA team knows how difficult it was to evaluate activities by RPN. RPN has two main disadvantages:
 

• assigning the same weight to all three criteria S, O and D
• no standard value from which the corrective action had to be taken.

The new criterion, which prioritizes the implementation of corrective measures, eliminates both of these shortcomings. The Action Priority matrix, AP for short, gives more weight to criterion S, i.e. severity. That is logical and reasonable. It also divides priorities into three groups: High, Medium and Low, defining the measures to be taken to avoid disagreements. This made it easier for the task force to decide which measures to implement immediately and which to implement later. This will help eliminate the risk of failure.

Seven Steps of FMEA
 

Previous FMEA manuals have defined the steps that need to be taken to successfully complete the analysis. The new version has partially changed them and requires implementation. Even to the extent that she entered them into FMEA forms.

Of course, to some the new procedure may seem too formalized and bureaucratic. On the other hand, it should be mentioned that the formal division of the FMEA procedure into seven, logically consecutive and interconnected steps helps the team to process the problem effectively on the basis of its gradual identification.

This requires a structural and functional analysis of the design or process before the risk assessment itself. For example, DMAIC projects have a similar approach and those who have experience with them know how useful it is to adhere to this cycle. On the contrary, non-compliance leads to bad conclusions and ineffective measures.

The new manual therefore logically used the knowledge from process management and introduced the mentioned seven steps. These steps force the team to work systematically and get to know the analysed product or process in depth. This minimizes the risk of incorrect risk assessment, incorrect determination of the root cause and the introduction of ineffective corrective measures.

On the other hand, they protect the team from external influences, which pushed for the closure of the analysis as soon as possible and the introduction of less demanding corrective measures. Unfortunately, often knowing that they will not work reliably.
 

New tables

The above changes have necessitated a revision of the scoreboards for the individual FMEA criteria. For example, for criterion S (severity), it describes the severity of the risk in three respects. From the point of view of the production plant, the customer and the end customer. This change will greatly facilitate the FMEA's work in determining severity, as it specifies more precisely how to assess the severity criterion.

The evaluation table of criterion O (Occurrence) did not avoid revision either. While the current table assessed the occurrence on the basis of a known or estimated number of irregularities, the new table highlights the nature of the measures put in place to correct the mistake. If we realize that the older version partly included the impact of fault detection, then the new approach is closer to reality.

It should be noted here that there is also an alternative evaluation table for criterion O in the new guide, which is identical to the older version. This makes it easier to process the analysis if the team is unable to assess the value of criterion O according to the new scoreboard.
A completely new table is the evaluation table for the AP, i.e. Action Priority matrix. The table lists all possible combinations of the three criteria S, O and D, and each combination is assigned a priority value that takes on values of High, Medium, or Low. Therefore, it is no longer necessary to calculate the value of the product of the criteria as in the case of the application of the RPN. For each AP criterion value, the organization's procedure for responding to the assessed risk is specified.
 

New forms and types of corrective measures

The revised forms take into account the seven-step process of FMEA implementation and thus formally record the findings of the researched problem. Deficiencies in the process or logic of team thinking are therefore easier to detect. This contributes to increasing the reliability and robustness of the whole method.

Another novelty is the introduction of two types of corrective measures to reduce the overall risk. One group is focused on reducing the incidence of failure, i.e. reducing the value of criterion O, and the other group on improving the detection of non-compliance, i.e. reducing criterion D. This will help set remedial measures that take into account both aspects of reducing the overall risk of failure.
 

Benefits of the new handbook

Finally, the newly published handbook contains significant changes in the analysis and is at a higher quality level than the previous handbook. The way FMEA is implemented is more structured, consistent and robust. At the same time, however, it gives work teams the opportunity to determine the values of individual criteria more easily and reliably, as well as a more logical way of prioritizing corrective action.

It also forces organizations to examine the nature of the problem being analysed more responsibly and thoroughly. Last but not least, it leads the organization to overall quality growth, which is conditioned by a thorough knowledge of its own processes and products.
 

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