Although I'm not too familiar with the process your talking about it
     may be the bridging is a consequence of using no-clean flux.  By
     definition the residue & therefore the anti oxidisation blanket some
     of the agents provide, in no-clean flux is less & therefore not as
     tolerant.  This can leave you open to oxidisation when exiting the
     wave culminating in bridging.

     You may be getting a similar effect (flux burning off prematurely) by
     having the pins in the wave too long.  without more information it's
     difficult to cover all aspects without writing War & Peace!

     Regards Iain.


______________________________ Reply Separator _________________________________
Subject: [TN] solder fountain process
Author:  Lik-Jen.Wu.lwu ([log in to unmask]) at Internet
Date:    12/28/98 9:22 PM


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Hi! I am using a solder fountain process to solder a PGA processor chip on a
double sided board. This is a fairly new process to me and we are getting
solder bridges on some of the pins on the PGA chip. The board is preheated
before it hits the solder fountain. The top side temperature of the board is
150C (220F), the solder temperature is 260C (500F) and no-clean flux was
used.

I wonder if anyone out there has had success in using solder fountain to
solder PGA.

Thanks,
Lik-Jen Wu
Nortel Networks (Wireless)
Manufacturing Engineer
Tel: 403-781-4612 Fax: 403-232-4321
ESN: 760-4612 email: [log in to unmask]

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