Re: PFMEA rating - Some clarification
Whether the Occurence rating and detection rating are given for the Potential failure mode or for the potential cause??
Thanks.
Yes, this does get confusing and the AIAG manual doesn't help too much.
If we have one potential cause, then we rate the potential failure mode rather than the cause.
If we have 3 potential causes to one failure mode, here is what I would suggest.
Rate the potential failure mode first from 1 - 10 on occurring. Let's us say it is a 6. Now rate the causes independently but one must make sure that they end up with an average of 6. Let's say potential cause #1 is a 8, #2 is a 6 while #3 is a 4. What do we have? An average of 6.
If we rate the potential failure mode a 4, we would could have cause #2 a 6, cause #2 a 4 while cause #3 is a 4.
I have seen so many times when one would rate a cause quite high but the potential failure mode really had a low rating and your company could end up spending a lot of $$ correcting a cause that contributes to a potential failure mode that would rarely happen.
As far as the detection rating, it does relate to catching potential causes (per AIAG
FMEA 4th edition) but there may be certain cases where is must be applied to a cause also. It does depend.
Hope this helps a bit.