Hello  Marty,
We mostly use Allied Signal A11-108 No Flow Prepreg; formerly an old
Westinghouse Fortin product.  It pretty much has been the Industry
Standard for some time.  Use 1 ply if the design is "pads only" outer
layer and 2 plys if bonding over conductors.  Pressure must be kept low.
 Use your CAM station to calculate the surface area of the heat sink not
the board.  Multiply by the number of parts you are running in one
opening. Keep the pressure between 50 -75 psi.     Use manual low
pressure cycle.  Heat rise should be a nominal of 12 degrees / min.
between 180 -280 degrees F.  Cure at 345 F for 1 hour.  Do not let your
press over shoot on temp and melt the solder on the board.  Also use a
pressure equalizer pad and release sheet in your caul plate lay up.
Allow to cool slow under pressure at no faster than the  heat rise to
minimize warpage.

Good luck.

Don Dupriest
Lockheed Martin
972/603-7724
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From: Sheppard, Marty - LYPME
To: [log in to unmask]
Subject: [TECHNET] Heatsink lamination