What is the real purpose of a Certificate of Conformance "C of C"?

[SteelMaiden]

Guys, sometimes certs are valuable to a process because they provide specific information and not just a regurgitation of what the original spec was. In my days in the cold drawn/heat treat segment we used the actual chems as certified to set temps and soaks. Without knowing the exact chems, we could very easily fail to meet the heat treating requiremnts. One point of Carbon could require a 350 degree temperature change dependent upon drafting practice. I agree that certs are probably not required for some industries, but once again, never say never.

 

[QChas]

I have been trying to educate customers for years on this one. The PO is the contract. If I make the parts to that I certify they are good! To me the C of C is like buying a pair of Fruit of The Loom underwear. Do I really need the little "Inspected by #7" paper?

 

[sfkevin]

Everything g notes is correct, as a contract manufacturer our end customer what this document to indicate we are building to the current drawing and revision level. They are also looking for proof that we a verifying and performing our process per RoHS requirements. The paper is only as good as the group issuing it.

 

[SteelMaiden]

The paper is only as good as the group issuing it.

Now, see, I have a problem with this statement. If you feel that this is correct, then one would assume that you are dealing with suppliers that are less than honest and/or competent. In which case I would say to you that you need to do a better job of evaluating your suppliers, no?

If I was hesitant about using the certs from a supplier, they would not be on my approved supplier list or at least have some sort of qualification, such as performing a retest myself IF they were the only supplier I could get the product from. But, once again, there are numerous reasons in my industry to get actual values on a cert and not rely upon only the ranges in the spec in the PO.

 

[sfkevin]

The majority of our suppliers are good, but yes, I have found a few that for one reason or other issued certifications that did not match the requirements asked for or stated they did and we found that they did not. Yes, we issued SCAR’s and confirm correction or dropped them as suppliers.

 

[gleclair]

I have been trying to educate customers for years on this one. The PO is the contract. If I make the parts to that I certify they are good! To me the C of C is like buying a pair of Fruit of The Loom underwear. Do I really need the little "Inspected by #7" paper?

Just a thought, why do some customers need to see your ISO certification before you can supply to them? The PO should be good enough then.
I Know it is a little off the topic but I thought it was interesting.

 

[martin elliott]

But, once again, there are numerous reasons in my industry to get actual values on a cert and not rely upon only the ranges in the spec in the PO.

I am sorry but I think we are extending the content of a C of C here as the whole point is that a C of C in europe under the reference I quoted earlier is that it does not have any actual results.

I personally don't permit purchase of raw materials for use here at this C of C level because I too need the true details to tailor processes.

 

[qualitytrec]

Ok I think I understand the difference between a CoC and a CoA. So why would a customer ask for both? Would not the CoA trump the CoC and thus make it un-necessary? I ask because I have a customer who has asked us to do both. In addition we are supplying the AQL results and process data from our distribution. It seems to me that a CoA should be enough and if their was an issue then to ask for the supporting documentation to prove the findings that were reported on the CoA. Am I wrong? What is the real purpose of a CoC? And if a CoA is issued why would there also need to be a CoC???

Mark

 

[MIREGMGR]

An example:

C of C says "we certify that we made this shipment of widgets per your 1" x 1" x 6" specification."

C of A says "per laboratory test, we have verified that the material we used for this shipment of widgets contains 0.25% unobtainium per your material specification."

At least for me, the C of C describes parameters that are engineering controlled, such as dimensions. The C of A pertains to a check-analysis of parameters that likely were controlled by your vendor's material supplier, therefore the C of A might be providing either more precise information than the general info that you otherwise might get, or a double check that the vendor's vendor actually supplied what they were supposed to supply.

We call them "certs". As a medical device manufacturer, we find them useful during audits and inspections to demonstrate that our vendors have acknowledged in regard to particular individual deliveries that they were aware they were subject to 21 CFR 820.50 purchasing controls, and that they have conformed to our procedures and specifications.

 

[Crusader]

I have a question on this topic. If an organization is registered to a standard such as ISO 9001:2000 or similar, why on earth would the customer even/want need a CofC? Doesn't the registration trump any CofC? (provided that there are NO special customer requirements.)