Control Plan (Product/Process specification/ Tolerance) acceptance

[It Was I Who]

Hi.
Long time since i was here but now i need your help.

It's related to what to accept under the specific column (Product/ Process Specification/ Tolerances).
In AIAG it says "Specifications/ Tolerances may be obtained from vqarious engineering documents, such as, but not limited to, Drawing, Design reviws, Material standards, Computer aided design data, manufacturing, and/ or assembly requirments." So it says out from my perspective that you need to reference to "Hard controled documents"

So i have an issue with an supplier that fills this column with (As an example "Accordingly to instruction, Or accordingly to setup instruction and similare)
Out from my perspective that is not correct and it will creat a cirkel reference. It will not be able to be audited, you will not be able to verify if it is correct or not becuase it will never be wrong. and it will never help you if you have an problem that requires deeper digging into the C-Plan's.
What iwould like to see here is acctualy, a specific number with an tolerance, pointing towards an drawing, standard or as i would like to call them a "Hard dokument"

Please advice in this issue. and i hope i made my question right so get my point

Br Tommy

 

[John C. Abnet]

The product requirements are established by whomever is doing the product design (generally the customer, but obviously not always).
The process to achieve the product results is most commonly established by the organization doing the work, with no direction/requirements from the product designer.

Product design:
While the requirements are generally captured in a "hard controlled' document (i.e. drawing, industry standard, etc..) that is not always the case. There are often expectations (automotive seating/trim for example...i.e wrinkles, sink, power seat "feel", , ventilation fan "sound", etc..etc..etc..etc...) that may not be conveyed via a "hard controlled" document.

Process design:
As stated above, in most cases the Control Plan IS the "hard controlled" document on which the manufacturer captures the process controls needed to meet the product requirements.

Hope this helps.

Be well.

 

[Howard Atkins]

Hi.
Long time since i was here but now i need your help.

I
So i have an issue with an supplier that fills this column with (As an example "Accordingly to instruction, Or accordingly to setup instruction and similare)
Out from my perspective that is not correct and it will creat a cirkel reference. It will not be able to be audited, you will not be able to verify if it is correct or not becuase it will never be wrong. and it will never help you if you have an problem that requires deeper digging into the C-Plan's.
What iwould like to see here is acctualy, a specific number with an tolerance, pointing towards an drawing, standard or as i would like to call them a "Hard dokument"

Please advice in this issue. and i hope i made my question right so get my point

Br Tommy

A contolled "hard "document can be a work instructon or any other typeof document.
As an auditor I will lookm at the work instruction or set up instruction and audit as per the referenced document.
In many cases it is easier to update the reference document ratjer than the control plan and often the document for the operator is not the control plan

See also Control Plan use on the manufacturing floor
for further discussion on this idea

 

[It Was I Who]

Hi howard/ Jhon

But if i say "As control instruction or as work instruction. What will i audit from.
My point is, if the C plan say "acc to WI, then i will look at the WI to get what it should say and the second after look at it again to see if it is the same. And ofc it will be. The C plan looses its intent to be a control document to ensure the that the process description ( Work instructions and control instructions are correct and that the process is described in a reflecting way and that the production follows the correct process description.

To make it extrem.. you would only need one line saying produce acc to instructions for the whole process. and the control plan will loose it's purpose to help you in the case of a hard problem to solve.
I have a hard time to see how it can be that way.
How will you see if the work/ Controlinstruction is correct accordingly to what has been developed from the begining.

Perheaps i can't describe what i mean. But for me the c plan losses its purpose, and you could instead have a binder with all the instructions and skip the C plan.

Tommy

 

[John C. Abnet]

Good day @It Was I Who ;
Keep in mind, beyond specific customer requirements/agreements, the specific information stated within the Control Plan is up to your organization. There is a specific protocol/methodology for how the control plan to be used, but beyond that, it is up to the organization creating and the customer who is accepting.

Having said that, I will give you my professional opinion related to my experiences...

For example, I have worked with organizations that perform thermal processing, i.e. "heat treat".
These organizations generally consider the details of the process as proprietary.

In those situations, I would council that identifying WHAT is being measured be recorded on the control plan. However, the actual SPECIFICATION can then point to a specific set of information (e.g. work instruction, etc..etc..)

For example:
A typical heat treatment process may include the following specifics...
* Austenitizing temperature
* Quench agitation rate
* Quench temperature
* Draw speed
* Draw temperature


In those cases, as a consultant/customer I would suggest/require that instead of listing "heat treat" generically as the process and then referring to a controlled "document" which contains all the details, state on the control plan the actual individual process items as I have shown above. The actual specifications for each of those, however, can (should be if proprietary), simply point to the controlling "document". During an audit, it is then typical to allow verification of the process to those proprietary values, BUT not allow copy or otherwise disperse those proprietary values to the auditor / customer.

Hope this helps.
Be well.

 

[It Was I Who]

John
You are touching the point, i agree to that you should stat in the Cplan what you are mention above and you could point towards a document, but i would preffere that that document is an Standard or an routine. rather then the WI/CI itself.

I could ask the question the other way around insteed.
What do you need the C plan for? You have all the information in the WI/ CI ?

And how and what will you use to do an audit or ensure that the process is in order? what should you compare it towards. you will never have any information or evidence that they are out of specification, as long as they do as the WI/ CI says.

I'm starting to think of the munk at the monestary that wrote wrong in the bible when he was set there to do so in the late 1500. He wrote Celebat istead of celebrate. A thing like this would never be found if you don't compare from an original.

Why i'm so hard in this question is due to that i have had an deviation ( Major) from an IATF audit on just this point.

And i'm a hard nut to convince.

Br Tommy

 

[TWA - not the airline]

I think, the question "what do you need the control plan for" is actually quite important. So who does use it and for what purpose?
I'd bet the deviation comes from the auditor who used the control plan as an easy way to conduct the audit, i.e. as a kind of checklist. So what exactly was the problem? Was there really a chain of references that lead nowhere or went in circles? Or was in one case the information in some way special and no one during the audit knew/could explain where the initial requirement came from and could be found but it did exist?
What would happen, if - in order to please an auditor - you created lots of redundant specific information (instead of references or chains of references to one master location of the information) that you cannot keep correctly up-dated when requirements change?
My

 

[John C. Abnet]

What do you need the C plan for

What do you need the C plan for? You have all the information in the WI/ CI

The Control Plan is (should be)...
* the organization's bible for making a widget.
* It is spawned by the PFMEA.
* "One stop" guideline that leads to all controls necessary to manufacture the widget.
* The document that should go into every corrective action meeting so you can compare what happened with what should have happened. \
* The contract with the customer, committing to how your organization will control the manufacture of said widget.
* Allows the ability to "point to" proprietary information so it does not need shared with customers/others.


The WI (or other such documents) should only be created as necessary. Should be limited to a single (or few) process step(s). Should be in terms and methods to communicate to a different audience than the control plan (i.e. the operator). It contains any/all proprietary details that the operator/team need. It should be the point-of-work information that is "linked" to that specific process step on the control plan.

Good questions. Keep being a "hard nut". Always ask for proof. Always beg to be convinced.

Hope this helps.
Be well.

 

[Jim Wynne]

The first time that a customer will see a control plan (typically) is in reviewing a PPAP submission. At that stage, there is no easy access to the supplier's internal documents. For this reason alone, the Product/Process Specification/Tolerance column should never refer to extrinsic information. The specifications/tolerances for part and process requirements should be explicitly cited, as well as the Evaluation/Measurement Techniques. There should be no exceptions, ever. The only place where references to internal documents should be used is in the Reaction Plan column, because there generally isn't enough room there to provide all of the necessary information.

 

[Johnnymo62]

I think the Control Plan is just that, about controlling the process, not about how to make something.

It's a list of "controls" to verify the product was made to meet the customer's requirements and mitigate risk found in the PFMEA.

The CP is developed from the Process Flow Chart and the PFMEA.

The PFMEA comes from the DFMEA which should be developed from the drawing, PO, standards that apply, etc.

The Process Flow is just a representation of the sequence of the processes used to make and control the product, as determined by the APQP team.

So, I agree with the OP. The CP should have specific values for pass and fail listed.