Contents of PPAP Control Plan - Product & Process Characteristics?

Hello, everyone.

I'm wondering if I can get a bit of advice on the content of a control plan. I understand the concepts, I think, but some of the fields seem a bit vague as to how to fill them in, and exactly what needs to be in there. I'm very new to PPAP, and I'm trying to prepare a submission to our customer.

I don't entirely understand the content of the "Characteristics - Product" and "Characteristics - Process" fields. From the few samples I've found, I see, for example, "bolt torque" in the product field and "torque driver torque monitoring" in the process field. So, just what is meant by "Product"?

The second question is to do with content. It seems that every process, from incoming inspection to outgoing shipment, is entered, along with the control methods. So, as an example, for a process that involves putting the part into an oven for some time to bake, do I need to note how the oven temperature is set by the operator, and also how it is controlled (by the hardware of the oven), and also how we might calibrate that hardware periodically? Is that the kind of detail I need?

Thanks for the help!
Len

Re: PPAP control plan

lenbh said:

Hello, everyone.

I'm wondering if I can get a bit of advice on the content of a control plan. I understand the concepts, I think, but some of the fields seem a bit vague as to how to fill them in, and exactly what needs to be in there. I'm very new to PPAP, and I'm trying to prepare a submission to our customer.

I don't entirely understand the content of the "Characteristics - Product" and "Characteristics - Process" fields. From the few samples I've found, I see, for example, "bolt torque" in the product field and "torque driver torque monitoring" in the process field. So, just what is meant by "Product"?

Click to expand...

Perhaps this example will help. If you were machining a bolt, the "Characteristics - Product" would be the hex dimensions, length dimensions, even some of the thread dimensions - those characteristics found on the product itself. The "Characteristics - Process" would be the machine controls - feeds and speeds, chuck pressures, etc. - those characteristics that might affect the outcome quality that are not directly on the part.

lenbh said:

The second question is to do with content. It seems that every process, from incoming inspection to outgoing shipment, is entered, along with the control methods. So, as an example, for a process that involves putting the part into an oven for some time to bake, do I need to note how the oven temperature is set by the operator, and also how it is controlled (by the hardware of the oven), and also how we might calibrate that hardware periodically? Is that the kind of detail I need?

Click to expand...

Every sequence of your process should show up on the control plan, Any verification you do, or control you have in place, you need to take credit for on the control plan. The last column should state what you really do if the process goes wrong for that line item. The detail needs to make sense. If it appears to be too much detail, it can be spun off into a work instruction (step-by-step stuff) and referenced int eh control plan.

Hope that helps....

Re: PPAP control plan

That makes a lot of sense, and clarifies it. I didn't think it was that complicated... just needed to understand what was expected.

Thank you very much!

Re: PPAP control plan

One other thought - do not look at the control plan as info to satisfy an auditor or customer. Think of it as a guide for your own people. If you walked up to an operation, it should be a simple guide as to what you need to check to verify the parts and process, how you are going to do it, with what gage, how often, and what to do if you run into a problem. Really, that was all the chart was designed to do.

Re: PPAP control plan

Ahhh... Right. It's often too easy to think "what does the auditor want" and not "what do we want".

Thanks again!

Len

Re: PPAP control plan

I agree with Bob's example for Product & Process characteristics.

Here is some food for thought regarding the 'content' of the control plan. There is no written specification, rule or requirement that forces you to list all your process steps (from receiving to shipping and anything else in between) on the same control plan. As a personal preference I like to develop control plans for every major process then compile them as they apply to a particular part. This enables me to have CP's for standard/common processes (i.e. receiving, storage, handling, shipping, etc) and not re-create them for every new part. Of course that does not mean that I shouldn't review them to ensure that they are still valid and effective. As a side note, this approach also implies process-specific PFMEA's as opposed to a cover-all PFMEA, since the CP is derived from the PFMEA. Some of the benefits of such an approach:
- smaller and easier to manage control plans (fewer sheets of paper) for each process
- reduced CP development time on new products
- ability to modify one process without modifying the CP for all other processes
- have only relevant information at every process (i.e. receiving CP at machining process does not help any)

Another bit of food for brain ... It is advisable to focus your controls on process parameters/charactereistics in order to build the quality into the part, as opposed to using part characteristics to detect quality. Use the part characteristics primarily to validate and re-validate your process.

Hope this helps some.

Re: PPAP control plan

What you suggest makes a lot of sense. I have several sets of processes that the part has to go through - receiving, forming, machining, etc. and we could easily break up the control plan into blocks like that.

Thanks for the ideas.

Cheers.
Len

Re: PPAP control plan

DrM2u said:

Here is some food for thought regarding the 'content' of the control plan. There is no written specification, rule or requirement that forces you to list all your process steps (from receiving to shipping and anything else in between) on the same control plan.

Click to expand...

Conceptually, I agree. My preference is to have them in the same file (for easier document control), but be able to print them out by operation. Few people care to look at other operation's controls - they just want to know their own. You could even make them individual tabs, if your preference is Excel.

Re: PPAP control plan

bobdoering said:

Perhaps this example will help. If you were machining a bolt, the "Characteristics - Product" would be the hex dimensions, length dimensions, even some of the thread dimensions - those characteristics found on the product itself. The "Characteristics - Process" would be the machine controls - feeds and speeds, chuck pressures, etc. - those characteristics that might affect the outcome quality that are not directly on the part.



Every sequence of your process should show up on the control plan, Any verification you do, or control you have in place, you need to take credit for on the control plan. The last column should state what you really do if the process goes wrong for that line item. The detail needs to make sense. If it appears to be too much detail, it can be spun off into a work instruction (step-by-step stuff) and referenced int eh control plan.

Hope that helps....

Click to expand...

It's all good advice. I've seen far too many control plans where the process characteristics column is completely blank, and what you have is an inspection plan, which defeats the purpose in large measure. It should be a process control plan.

Re: PPAP control plan

Jim Wynne said:

It's all good advice. I've seen far too many control plans where the process characteristics column is completely blank, and what you have is an inspection plan, which defeats the purpose in large measure. It should be a process control plan.

Click to expand...

I agree with Jim. Most control (quality) plans are reactive in nature.
Also, the relationship between process characteristics and product characteristics is poorly understood and/or ignored.

Stijloor.