Guys, 

I didn't weigh in before but +/- .016" from what?  I tooling hole to the 
edge? 

If I'm building you a board 18: x 24" and you want that tolerance for the 
routing of the outside edges I'm not bidding.

my thoughts,

Chuck


Charles W. Brummer | 3M Manufacturing Engineer
3M Electronic Solutions Division
3M Canoga Park, 8357 Canoga Ave. | Canoga Park, CA 91304
Office: 818 734 4930
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From:   "Scott A. Bowles" <[log in to unmask]>
To:     <[log in to unmask]>
Date:   08/05/2015 07:08 AM
Subject:        [EXTERNAL] Re: [TN] PCB length/width tolerance
Sent by:        TechNet <[log in to unmask]>



Bob,

Maybe you can clarify what is driving your question.  You state that the 
±.016" seems liberal (and I agree) but this is our subjective opinion. Are 
you asking from a design/OEM perspective or manufacturing/supplier 
perspective? Section 3.4 of IPC-6012 states the printed board shall meet 
the dimensional requirements specified in the procurement documentation. 
However, if there truly isn't any requirement specified then you default 
to the applicable design series specifications. I would think it is very 
rare for a drawing to have no requirements, to not even have the "Unless 
Otherwise Specified" title block tolerances on sheet 1, which typically 
default to something along the values of three place decimals ±.005", 
two-place decimals ±.010".

From a design perspective, IPC-2222A, paragraph 5.4.1 states the 
tolerances specified on the drawing shall accommodate the dimensions and 
tolerances of the mating part.

I suggest clarifying the requirement before manufacturing product.

Regards,
Scott
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