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Reply To: | TechNet Mail Forum. |
Date: | Mon, 15 Dec 1997 16:48:15 -0600 |
Content-Type: | text/plain |
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Hello, TechNetters,
I was wondering what others are calling out for flatness requirements on
double sided boards with surface mount components. IPC-A-600 calls out
1.5% but with a caveat that automated assembly and surface mount may
require more stringent requirements, and refers to IPC-D-275. The most
stringent callout in D-275 for a 0.062" double sided board is 0.9%, and
this is classed "reduced producibility". If we have, say, an 8.5"x11"
board with 0.9% bow or twist, I know we'll have difficulty running it down
our lines. What are others calling out, and how have your fabricators
responded? Some of mine are balking at 0.7%, saying it can't be held
(would have to be sorted, possibly increasing cost) because of variability
in the base material. I think 0.7% is met most of the time, but every once
in a while...
Thanks for any input.
*****************************
* Pat Bailey *
* Supplier Quality Engineer *
* Zytec Corporation *
* 1425 E. Bridge Street *
* Redwood Falls, MN 56283 *
* *
* phone 507 637-2966 x355 *
* fax 507 644-3720 *
* e-mail [log in to unmask] *
*****************************
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