Howard,
        Would you provide me with more information like:
1. How long you have been using Thermabond?
2. What is the life expectancy of the application (i.e., will the
Thermabond still be adhering the heatsink to the pwb near end-of-life?)?
3. What environmental conditions (temp & humidity extremes) will the
Thermabond be exposed to?

        Any info in this area would be quite helpful.

Thanks,

Mike Adams
Lucas Aerospace
[log in to unmask]
(216)995-1195 x3058

> ----------
> From:         Howard Feldmesser[SMTP:[log in to unmask]]
> Sent:         Thursday, October 16, 1997 4:24 PM
> To:   [log in to unmask]
> Subject:      Re: [TECHNET] Heatsink lamination
>
> 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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