PFMEA repetitive failure modes in subsecuent stations.


Starting to get Involved
Hi greetings,

Hi coming across with a PFMEA , it had some failure modes causes by incorrect assembly operation by production operators, all with its correspondent controls, the thing is that this particular cell had a tester station that checks the precise result of what the operator has done, and it has (again) a failure mode " incorrect assembly by the operator", along with the same controls aside from adding red rabbits for the detection's, my understanding is that only failure modes that can be affected by the particular station process should be included in that station, then since that station only checks this condition, is it ok to repeat them?



Involved In Discussions
There is a discussion in the Cove about how to tackle inspection stations in a PFMEA - In-Process Production Test Stations in PFMEA (Process FMEA) . I have to agree with the contents: the failure mode "assembly operation" already includes the detection as per the tester station. Hence when you reach the tester, the requirements are no longer to "assemble correctly" but to detect correctly. Here you will have to ensure OK parts are approved and NOK parts rejected and segregated. Also that there is no bypass of the test.

You do not necessarily have to include the tester station in the PFMEA, by the same reason for which you probably do not include an analysis for a failure mode stemming from a variable inspection with a caliper. That being said, I do include tester stations, as described above.

A further remark, if I may. Do not put the spotlight on the operators for an assembly error. I would rather attribute a cause to the design of the manufacturing process, which left a station without mistake or error proofing, or maybe just due to the nature of the operation or the context of the project did not justify to have an equipment or automatic operation.

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