PFMEA Detection Controls and Ranking - Prevent Shipment

Z

Zbigniew Huber

Hi,

Regarding detection controls in PFMEA the AIAG manual, page 99 says:
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When more than one control is identified, it is recommended that the detection ranking of each control be included as part of the description of the control. Record the lowest ranking value in the Detection column.

Assume the failure has occurred and then assess the capabilities of all "Current Process Controls" to prevent shipment of the part having this failure mode.
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How to properly interpret the text: “Assume the failure has occurred and then assess the capabilities of all "Current Process Controls" to prevent shipment of the part having this failure mode”

Prevent shipment from one operation to next operation or prevent shipment from the factory/line?

Let’s assume following situation:

A defect occurs at op.80.
The control method for it is visual inspection at op.80, then visual inspection at op.120 and then the failure mode is detected at an EOL (end of line tester) op. 280 with automatic part lock when failed.

I always included all controls for the specific failure mode (when evaluating op.80) in the following manner:
- visual inspection at op.80 (7)
- visual inspection at op.120 (8)
- EOL final test op. 280 (4)
And then the detection ranking in the detection column was 4.

I saw a PFMEA where only detection present at the op.80 was considered as valid for detection ranking for the failure mode (the op.120, and op.280 was not considered at all).

What approach would you recommend?
 
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A

Al Dyer

Automatic lock on failure at OP 280???

You say you saw a PFMEA where...........??

Sounds like you already have a good handle on your PFMEA structure and control. Don't worry about how others do it, let others ask about how you do it.

These things are so individualized to the specific process, just remember that the end goal is a good part for the customer. Do it your way.

Al...
 
Z

Zbigniew Huber

Automatic lock on failure at OP 280???

Al...

The end of line tester (EOL at station 280) detects the failure mode (missing small part in a manufactured product) and then prevents the defective part from subsequent processing. The failure mode is caused at op.80.

You say you saw a PFMEA where...........??

Al...

I saw a PFMEA of very similar process at different company. They also have EOL tester and process is very similar but their PFMEA does not include failure mode detections in subsequent stations (post processing). I would like to know if such approach is correct or not.

Sounds like you already have a good handle on your PFMEA structure and control. Don't worry about how others do it, let others ask about how you do it.

Al...

Thanks.
 
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