Chris -

First step - has anyone looked at a cross section of the board to determine
whether or not the dimensional spacing of the layers is as desired?  If they
are not, then clarification of the design and a bit of work with the fab
house may solve the problem.

If you need step 2, shoot me an Email with your findings and we'll have a go
at it.

Regards - Kelly
-----Original Message-----
From: Chris Bartkowiak <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Monday, September 27, 1999 1:29 PM
Subject: [TN] Warped PCB's


>Friends:
>
>I have a 6 layer board that warps.  The R&D group tells me its a
>Manufacturing problem. I'm not so sure.
>
>Details:
>.062" Thick NEMA FR4
>Stack: (Trace/Gnd/Trace/Trace/Power/Trace) w/1/2 oz copper clad.
>R&D group tells me the layers are balanced from the center of the stack
>out.
>
>What should Manufacturing be doing to prevent these boards from
>warping?  Or is the only solution a higher temperature
>FR4 material that adds cost to the board.  Could it be a problem with
>the board house. Please advise.
>
>Regards, Chris
>
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