FMEA: Visual Detection Rating

[bobdoering]

And for your Customer - they are correct in challenging your scale - however you are incorrect because you were unable to justify that scale!

This is true, and - yes even though a "suggested evaluation criteria" - you are likely going to see the customer permitting you to adjust you definitions to more clearly match your detection methods to the FMEA scoring guideline intent. If you look at the columns "Opportunity for Detection" and "Likelihood of Detection by Process Control" (Table Cr3, Page 100, AIAG FMEA 4th Edition) you are also likely to have them looking at the rankings to meet the intent of those definitions. Does your visual inspection definition of Rank 3 detect the failure automatically and prevent further processing? No? Then the customer may simply imply that you are diluting the intent of the rankings. They want 3 to represent a controlled detection, and one that prevents further waste of resources by processing a part after the defect has been generated.

Remember, you customer has the final vote, that is they decide to approve your PPAP based on the FMEA being effective. They are not obligated to approve a PPAP with an FMEA that they feel is inadequate based on their belief you used diluted scoring - no matter how attached you may be to your ranking system. Some customers have gotten past that whole issue by providing their scoring system, which is not "suggested", as a part of their customer specific requirements.

 

[Jim Wynne]

This is true, and - yes even though a "suggested evaluation criteria" - you are likely going to see the customer permitting you to adjust you definitions to more clearly match your detection methods to the FMEA scoring guideline intent. If you look at the columns "Opportunity for Detection" and "Likelihood of Detection by Process Control" (Table Cr3, Page 100, AIAG FMEA 4th Edition) you are also likely to have them looking at the rankings to meet the intent of those definitions. Does your visual inspection definition of Rank 3 detect the failure automatically and prevent further processing? No? Then the customer may simply imply that you are diluting the intent of the rankings. They want 3 to represent a controlled detection, and one that prevents further waste of resources by processing a part after the defect has been generated.

Remember, you customer has the final vote, that is they decide to approve your PPAP based on the FMEA being effective. They are not obligated to approve a PPAP with an FMEA that they feel is inadequate based on their belief you used diluted scoring - no matter how attached you may be to your ranking system. Some customers have gotten past that whole issue by providing their scoring system, which is not "suggested", as a part of their customer specific requirements.

Good points, imo, and another thing to consider is that if a given operation in a PFMEA is given a high severity rating, that alone doesn't mean that there's anything that can be done beyond what's planned, such as visual inspection. If the cost of "improving" something is greater than margin will bear, it's not going to be done unless the customer is willing to assume the additional cost.

This is another place where contract review and APQP come into play. If you foresee unusual costs (e.g. the cost of an automated vision system to obviate the risk of human visual inspection) you need to use that information in your early dealings with the customer. Give the customer options, with associated costs, and let them decide.

 

[bobdoering]

This is another place where contract review and APQP come into play. If you foresee unusual costs (e.g. the cost of an automated vision system to obviate the risk of human visual inspection) you need to use that information in your early dealings with the customer. Give the customer options, with associated costs, and let them decide.

That's where a lot of people miss the boat, because they do not want to invest the time to prepare the FMEA until after they have the quote accepted. They might do feasibility, but FMEA is when the ugly underbelly - especially when you look at it honestly - comes out. After the quote, it could be too late. Too late to increase price, too late to ask for gaging dollars.

And the gurus (who, by the way, aren't paying for your equipment) will tell you that the process needs to be robust enough to eliminate the scrap, and you should not inspect quality into the output. Prevention.... But, it has a cost too - one that the customers may balk at. The customer will go to the guy who quotes lower and...go figure...inspects quality in anyway. But, if it was easy, anybody....anywhere...would do it.

 

[Richard Pike]

you are also likely to have them looking at the rankings to meet the intent of those definitions.

Now that's an excellent clarification - one that I shall use for future "persuasion" of my Clients Customers - thanks

 

[29MJW29]

Hi, Core tool book shows a minimum score for visual inspection is 7 the feature has to gauged in some way to score less.

 

[Jim Wynne]

Hi, Core tool book shows a minimum score for visual inspection is 7 the feature has to gauged in some way to score less.

Welcome to the Cove.

The AIAG manual represents guidelines, and following them may or may not be required by customers, as was mentioned earlier in the thread.