---------- Forwarded message ----------
Date: Wed, 16 Aug 95 13:53 CDT
From: Letsinger, John F. <[log in to unmask]>
To: TechNet-request <[log in to unmask]>
Subject: RE: Copper Core PWB Assembly


Good luck with this.  You are probably most worried about building these 
boards right now, but chances are, you'll need some repair/rework done to 
them.  From a repair standpoint, your technicians are going to have to 
change some of their techniques.  These types of boards dissipate heat 
rapidly, and you may have a difficult time removing/replacing  components. 
  I'd recommend prebaking before starting a repair.  130 degrees F. for a 
hour or so will get rid of most of the moisture in the board.  Start your 
repair as soon as you can after removing the board from the oven.  You may 
have to use edge rail heaters in order to get enough heat in the board to 
reflow connections.  Ovens help, hot plates do too, but edge rail heaters 
are the most convenient and easiest to use.
     IPC-700C is a good source of repair information, although it is getting 
a little long in tooth (8 years old).

 ----------
From: TechNet-request
To: TechNet; ANDERS P. PEDERSEN
Subject: Copper Core PWB Assembly
Date: Wednesday, 16 August, 1995 09:02


          We are about to order some sample copper core boards for a
          power supply assembly.  The copper core will be .050 thick
          in the middle of a 6 layer card.  All component mounting
          holes will be isolated from the core, but there will be some
          "ground" vias tied to the copper core.

          We have never assembled a copper core board before, and our
          manufacturing guys don't know what to expect.  Are there any
          basic guidelines that should be followed when assembling a
          core board?  Any little tid-bits we should be aware of?

          Thank you for any input or guidance.

          Andy Pedersen
          Harris Corporation
          [log in to unmask]