B
Hello,
Currently I am trying to make a PFMEA Guidelines for our company (automotive microelectronics).
Here is my suggestion about how to give priorities of the corrective actions:
Recommended actions
Prioritize recommended/ corrective actions in the following order:
A. Actions are mandatory for ALL Failure modes resulting in a Severity of 9 or 10
B. By the “Seriousness” = Severity x Occurrence
High Severity values, coupled with high Occurrence values merit special attention (require Recommended actions). Actions are recommended for any Severity of 5 or higher with an Occurrence of 4 or higher
C. Actions recommended for any failure modes resulting in a high RPN regardless of Severity X Occurrence combination (Use Pareto technique to prioritize the highest RPNs).
Apply Pareto principle 30/70 which means:
30% of causes produce 70% of the troubles.
You should work towards RPN reductions until RPN became to be lower than 32. If RPN < 32, and A and B cases are not valid, then Corrective actions are not required anymore.
So, my question is regarding this RPN limit (<32) from which applying corrective actions is not feasible anymore.
How this number was obtained:
8x2x2 = 32 => Severity 8 combined with Occurrence 2 and Detection 2 I consider to be no more danger. The other variant is 8x1x2 = 16.
What is your opinion? What is the practice in your companies? Although PFMEA is continual improvement process it is not feasible to try to reduce the RPNs at any cost. We should stop at certain point.
Thank you,

Currently I am trying to make a PFMEA Guidelines for our company (automotive microelectronics).
Here is my suggestion about how to give priorities of the corrective actions:
Recommended actions
Prioritize recommended/ corrective actions in the following order:
A. Actions are mandatory for ALL Failure modes resulting in a Severity of 9 or 10
B. By the “Seriousness” = Severity x Occurrence
High Severity values, coupled with high Occurrence values merit special attention (require Recommended actions). Actions are recommended for any Severity of 5 or higher with an Occurrence of 4 or higher
C. Actions recommended for any failure modes resulting in a high RPN regardless of Severity X Occurrence combination (Use Pareto technique to prioritize the highest RPNs).
Apply Pareto principle 30/70 which means:
30% of causes produce 70% of the troubles.
You should work towards RPN reductions until RPN became to be lower than 32. If RPN < 32, and A and B cases are not valid, then Corrective actions are not required anymore.
So, my question is regarding this RPN limit (<32) from which applying corrective actions is not feasible anymore.
How this number was obtained:
8x2x2 = 32 => Severity 8 combined with Occurrence 2 and Detection 2 I consider to be no more danger. The other variant is 8x1x2 = 16.
What is your opinion? What is the practice in your companies? Although PFMEA is continual improvement process it is not feasible to try to reduce the RPNs at any cost. We should stop at certain point.
Thank you,