Generic control plan - Check Part to Print

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Bill Ryan - 2007

Atetsade

I can't envision any time a Control Plan would be "larger" (by weight or volume) than a PFMEA. If your Control Plan is "growing exponentially", I would need to understand your Control Plan methodology. If something is not addressed in the PFMEA, it should not be "showing up" in the Control Plan.

As I read your post, it sounded to me as if you might be letting the Control Plan "drive" your PFMEA. This, if fact, is absolutely backwards.

Do all your nuts go through the same process flow (drilling, tapping, forming, thread rolling, knurling, boring, recessing, finishing, burnishing)? If so, a "generic" Control Plan might be a relatively simple excersize. You could certainly do operation specific CPs but if most of your nuts all follow the same flow, one CP should suffice. The "oddball" parts would then need their own Flow Diagram, PFMEA, and CP. The operation "doesn't care" whether a feature is a KPC, what size the threads might be, or what the material is made out of. It only "spits out product" as it was set up to do. The Failure Causes very well could (should?) be generic and that is how to approach a "generic" CP (and PFMEA). Once you have the "generic baseline", if your customer(s) require part specific documents, simply changing the header information and a couple of dimensional callouts on the CP (if you list dimensions - which goes away from the generic) should make life pretty easy.

Gotta run pretty quickly. I'd be more than happy to continue with this if you can give a little more detail of your operations.

Bill
 
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CINDY

All of our operators refere to our control plans. It is build into our system. Our control plans feed to the FMEA. If a characteristic is not on the CP how can it be on the FMEA?

Cindy
 
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Bill Ryan - 2007

CINDY said:
All of our operators refere to our control plans. It is build into our system. Our control plans feed to the FMEA. If a characteristic is not on the CP how can it be on the FMEA?

Cindy
I'll turn it back to you. If a Failure Mode (or Cause) is not addressed in the PFMEA, why would it be in the Control Plan?

To have the Control Plan "drive" the PFMEA is merely filling out paper and not truly embracing PFMEA. Sorry, I'm fairly passionate about PFMEA and to "do it backwards" just doesn't make much sense to me.

Bill
 
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CINDY

Bill,

We are monitoring the part characteristics in the control plan. Those characteristics, not all, but most are where the potential failures are from within our process for that part. We may also add to the FMEA, but the majority of the time, the control plan feeds the FMEA.

We thought that depending on each part characteristic, our control plan should have the limits build in. But I should also state that most of the time we build our own characteristics to monitor. We generally do not have special characteristics specified by the customer.

I never thought we were doing this backwards, please explain further.

Cindy
 
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Bill Ryan - 2007

I'm going to start down a path here. Please don't be surprised if I wander or get "lost".

The Control Plan is actually the third "step" in the "PPAP series of documents".

Step 1 is listing the processing steps (Process Flow Diagram (PFD)). This includes all steps the part goes through from receiving to shipping (including inspection, transfers, storage).

Step 2 is listing these processing steps in the far left column of the PFMEA. The Potential Failure Mode column lists part characteristics as defined on a part drawing, part model, or whatever means your customer conveys fit/function characteristics to you (each Potential Failure Mode needs a Detection method). The Potential Cause column lists those processing parameters/issues which can lead to the Failure Mode occurring at that operation/step. If you have a Prevention Control for a Potential Cause, it will be listed in that column on the PFMEA.

Step 3 is taking all the defined Potential Failure Modes (from the) PFMEA and listing them in the "Charateristic - Product" column of the Control Plan (once again at the appropriate operation/step). The "Characteristic - Process" column of the Control Plan lists all the Prevention Controls from that column of the PFMEA. The rest of the Control Plan, basically, details how you are "controlling" each product and process characteristic.
A well done PFMEA will virtually write your Control Plan for you.

If your Control Plans do not address the Process Characteristics then I submit to you that you have only a "product inspection sheet" and not a Control Plan. If that is the case, it helps explain to me how your Control Plan is "driving" your PFMEA.

I hope that helps explain my take a little.

Bill
 
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Sam

We use generic DFMEA's, PFMEA's and control plans based on product type.

Groo3,
I prefer to use "Keep it simply simple" (KISS)
 
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