I was involved in setting up a fluxless soldering process for a
distributorless ignition system for a major auto manufacturer. We used
ammonia, ran it thru a "CRACKER" at 1200deg. C, to crack the ammonia
into It's basic elements of Nitrogen and Hydrogen. We used the
hydrogen as the inert atmosphere, and nitrogen blankets at the end of
the furnace. The components to be soldered were on carbon boats. It
was an interesting 6 months of my life. Not sure if I would recommend
this process, but once set-up, it worked! If you really want the gorey
details, I could be coerced to reveal more info. Regards.
Jeff L. Hempton, Sr. SMD Engineer
United Technology Electronic Controls
______________________________ Forward Header __________________________________
Subject: Re: [TN] Fluxless Soldering
Author: Matthew Park <[log in to unmask]> at Internet
Date: 3/10/1999 10:09 AM
Richard,
This time, I guess, your design engineering manager is right. There is a
fluxless soldering process available. If I remember correctly, one process I am
aware is called *PADS* (Plasma Assisted Dry Soldering???). Wow... a fancy
jargon isn*t it? In this process, components or assembled boards are exposed
in a PADS treatment within a vacuum chamber. This treatment turns soldering
surface to oxide-resistant by modifying soldering surface layer. From there,
you can store components or assembled boards for a specified period prior to
wavesoldering, reflow or handsoldering. You don*t need to apply flux to allow
wetting, thus no cleaning is required.
This process is ok for a lab application or a small production run. I don*t
have the info handy, but I am sure I have it filed away in my filing cabinets.
I can dig out something for you if you need to look further.
Regards
Matthew
Norsat International Inc.
>>> Richard Hamilton <[log in to unmask]> March 10, 1999 8:46 am >>>
Hello fellow TechNetters,
Well, we were asked a question by the design engineering manager yesterday
if we had considered a fluxless soldering process. We are aware of a process
called Solid Solder Deposit (SSD), but not a fluxless process by name.
After the manager read us the email he got from one of the marketing types,
I tend to believe that he was referring to no-clean process because of a
reference in his note about cleaning boards at a previous manufacturer (TI).
My guess (oh how I hate to guess/assume) is that this marketing type has
just mixed up a couple of buzz-words together,.....kinda like 'military
intelligence'. I mean look at it, 'no-clean flux', I can see how a sales
person would want to shorten that to 'no-flux'. Now as usual, it is up to us
manufacturing people to invent the process that has been sold to the
customer!!
And as a side note: Steve -
Your comments on machine maintenance are RIGHT ON!! You couldn't be more
correct. Sometimes I cringe at the way some machines are treated, and the
surprise that goes on when it does drop out!
Thanks all.
Richard Hamilton
Clemar Mfg. / Rain Bird
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