At 13:00 24/03/98 +0000, you wrote:
>We currently have a board requirement for a 7 layer board.
>
>The design limits the modification to make it a balanced
>even numbered layup and to rearrange thicknesses.
>
>The cores are
>
>single sided cap with 3/8 oz. CU.
>.0039 core
>
>followed by
>.016  core  3/8 /  3/8 CU
>.016  core  3/8 /  3/8 CU
>.016  core  3/8 /  3/8 CU
>
>Question:  Does anybody have any ideas to help reduce the
>warpage that will occur on this type of layup?
>
>ROR,  Lagging,  Cool Rates, etc.....
>
>                                                                         thanks
>

   Hello

From the construction side you can split the 0.039" core to two cores of
0.016" cores one of them unclad laminate & you can put prepreg in overall
thickness of 0.007" between this two laminates ( probably you can take 2
plies of 2112 ). This will give you the balanced construction based on
0.016" cores.



Shabtay
Process engineering - ELTEK

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