You are not in compliance with the letter of the contract if you do not have a deviation or some other documented authorization to prove AABUS.
Do not depend on the customer signoff of the fabrication drawing to be sufficient, because of the industry standard order of precedence in the documentation hierarchy.
First comes the contract requirements, P.O. notes, then the fabrication print notes, then any exceptions to any referenced industry standards listed within a Statement of Work or a document detailing PWB Fabrication Requirements (exceptions and additions), then finally applicable standards. Something needs to be documented and approved by the customer somewhere within the technical data package to allow the thinner wall, in this example.
If you have a gentlemen's agreement with the customer, then document the requirement with a note on the fabrication drawing approved by the customer, as a minimum, and make sure the TDP has a list of revisions for each Configuration Management Item (CM), which would include the TDP for each assembly to be produced (assembly drawing, fabrication drawing, schematic, BOM, firmware list, CAD file, etc, by revision or issue number).

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Phil Bavaro
Sent: Tuesday, January 28, 2014 3:17 PM
To: [log in to unmask]
Subject: [TN] IPC-6012 Class requirements

I have a question about the intent of IPC-6012 class requirements.

Let's say we have a contractual requirement to design and fabricate PWBs to meet Class 3/A.

But during the design, we unknowingly document some attribute that does not meet 3/A on the PWB drawing (which I call "3/A minus").  An example would be copper thickness in the hole being less than .0015"

Then later I discover that 3/A requirements are more stringent than our design is documented to have.

Is this a problem or does AABUS cover our error?

I would have thought that we are not in compliance with the letter of the contract.

Any comments would be appreciated.
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