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Thu, 16 Oct 1997 16:24:19 -0400 |
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Marty,
We've had very bad luck with bonding heatsinks with prepreg, most
often resulting in a board that looks like a potato chip. Several years
ago we switched to Arlon's Thermabond with great success. We've launched
several satellites with bonded on heatsinks and all are still functional, a
true test of surviving rigorous use.
Howard Feldmesser
The Johns Hopkins University Applied Physics Laboratory
At 2:54 PM 10/16/97 -0400, Sheppard, Marty - LYPME wrote:
>We are attempting to attach a nickel-plated copper heatsink to a 10
>layer PWB per a set of manufacturing drawings that only states that "the
>heatsink shall be attached with prepreg". It does not call out a
>pressure, temperature, cycle time, or a type of prepreg. We have
>assumed that we would need a "low-flow" type of prepreg. We have tried
>some sample cards with a low-flow prepreg (PC-GF 108V by Westinghouse
>Fortin) that we have on hand; we have had good registration of the
>heatsink to card, but the adhesion has not been as good as we would have
>liked, and the heatsink seems to have been pressed "into" the board (you
>can feel the outline of the heatsink on the backside of the card). We
>ran the press at the lowest possible pressure we can for our press (15
>lbs).
>
>We are looking for suggestions from anyone who has experience with
>laminating heatsinks to PWBs.
>
>Thanks,
>
>Marty W. Sheppard / LYPME
>Manufacturing Engineering Support
>(912)-926-9632 DSN 468-9632 Fax: (912)926-7974
>email: [log in to unmask]
>
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