Where to place a Down Stream Gage Inspection on an FMEA

[qcman]

We have a little debate regarding where to place a down stream gage inspection on a FMEA. Hypothetically lets say you add a final inspection gage check (detection) 2 process steps down from where the feature is created. Would you place the inspection step in the section of the FMEA where it is created or where the feature is actually checked?

 

[Proud Liberal]

Re: Down stream inspection

I'd vote to put it wherever the feature is being created. The distance between that and where it's being inspected wouldn't affect your risk factors (only your internal scrap rates assuming your detection and containment activities are adequate)

 

[Englishman Abroad]

Re: Down stream inspection

I agree with Proud Liberal, consider the gauge as part of the operation that creates the feature. However you will have to increase the detection scoring, as the detection method is not inside the work station. (See AIAG FMEA scoring tables)

 

[ncwalker]

I'm going to disagree with the Proud Liberal and the Englishmen, though I normally don't.

Your process flow diagram will have it a few steps down, the steps in your process flow diagram should match your PFMEA and your Control Plan.

Further, it paints a different picture in your capacity calculations. If you have Process A then Process B then Check 1 and Check 1 is checking features in Process A and has say a 5% scrap rate for Process A, having it associated with Process A means you won't calculate capacity on B correctly. Because the 5% bad you make on A still have to consume cycle time on B to get to the check 1.

 

[Ron Rompen]

ncwalker is correct - the PFMEA (and Control Plan) all need to show the SAME STEPS as the Process Flow Diagram. If you are adding an inspection stage, then the failure mode (fail to detect nonconforming part) needs to be shown at that stage of the process IN ADDITION to the process step at which it is created.

 

[qcman]

Answer seemed very simple when I was asked. Of course any gage check should be conducted at the point where a feature is made but sometimes its not feasible. There is merit in both points of view but the flow chart and control plan match is what made me second guess. Thank you for your input.