In a message dated 3/1/00 12:35:26 PM Central Standard Time, [log in to unmask]
writes:

Hello Jason and Mike,

I hate to slightly disagree with my fellow professionals but vapor phase
reflow can be very beneficial for certain applications.  Mike, you mention
that vapor phase does not offer the controlled ramp of a convection oven.  If
you purchase a batch system you have infinite control of the preheat as the
preheat and reflow zones are totally disconnected.  I will agree that the
fluids are expensive but the operating and maintenance costs of the systems
are very reasonable.  As far as I know, you do not dispose of the fluids but
even if you did they are not a regulated substance.  As for not being
suitable for high temperature solders, you can purchase fluids that boil at
260 C.  Other advantages are ease of profiling, there are only two zones,
elimination of hot spots, inert gas for reflow and very efficient heat
transfer.  I'm not saying that vapor phase is for everyone but there are
applications where you might want to consider this process.  By the way
Jason, no you do not need support for the components for most applications in
two sided reflow.

Larry Tawyea

<< Jason,
         Stay away from vapor phase, unless you have a specific need for it.
 It can work well on large/thick laminates such as backplanes, but doesn't
 offer the controlled ramp and preheat dwells that convection ovens can
 provide. The fluorinated liquids are extremely expensive, and will encounter
 regulatory requirements in most locales for both use and recovery of used
 liquid. They will not work with high temp alloys, as the maximum
 temperatures are restricted to the boiling point of the liquid (215C for
 3M's Fluorinert).

 Mike McMonagle
 PCBA Process Engineering
 Telxon Corporation
 (713) 307-2443
 www.telxon.com

 -----Original Message-----
 From: Jason Gregory [mailto:[log in to unmask]]
 Sent: Wednesday, March 01, 2000 7:53 AM
 To: [log in to unmask]
 Subject: [TN] vapor phase reflow


 Hello techies!

 I am looking for anyone who has performed any qualifications on the
 advantages/disadvantages of vapor phase reflow. Particularly dealing with
 higher temp alloys. Is it the way to go? Is convection better? Who are the
 major manufacturers? Are silicon castments to keep the bottomside components
 from falling off mandatory? Any replies are GREATLY appreciated.

 Jason Gregory
 Production Manager
 Electrospec
 (713)784-4900
 (713)784-1194 fax >>

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