Wow, The overwhelming solution is to lower the pot temperature and skim
it off the top. This will have to be a project for an up-coming weekend
or evening.
I think somebody asked how long it has been since our last analysis or
did we drop pennies into the pot. The truth is (hanging head in shame)
we have been running the machine for 5 years and this is the first
analysis we have performed... to quote Steve Gregory - Woooo-doggies!
With age we all get smarter and I've just been enlightened.
Thanks to all of you for your responses.
Phil Nutting
-----Original Message-----
From: Lou Hart [mailto:[log in to unmask]]
Sent: Wednesday, August 15, 2001 9:21 AM
To: [log in to unmask]
Subject: Re: [TN] Solder analysis results
Any comment on Steve's stratification theory? A few years back I had
SPC
charts at a HASL pot at a PC fab, with analysis every two weeks. Cu
content stayed 0.21% to 0.24% over a period of 1+ years, even though all
we
were doing was skimming stuff off the top. Lou Hart
-----Original Message-----
From: Stephen R. Gregory [SMTP:[log in to unmask]]
Sent: Tuesday, August 14, 2001 10:04 PM
To: [log in to unmask]
Subject: Re: [TN] Solder analysis results
Dave,
Surely, not ALL 1700-lbs.? Wooo-doggies! I can only imagine what a task
that
would be!!! I've read some stuff that if you keep the pot static, and
keep
it
at a stable temperature for a period (what this really is, I don't
know...there's varying opinions), the metals will seek their own level
(according to the different opinions, the copper will be towards the
top),
then you scoop out out the top layer, and replenish what you've removed
with
fresh bars.
The question that I have though, how did the pot get so out of balance
with
copper? I've never had a problem with copper content, even when waving
OSP
boards...tin levels dropping, yes. But not excessive copper...somebody
throw
some pennies in the pot?
-Steve Gregory-
> RJ Klien Wassink suggests [bible p 169] pouring contaminated solder at
about
> 190°C through a 20 mesh stainless steel stariner to reduce copper
content
to
> 0.25%.
>
> Dave Fish
>
<< File: ATT00002.htm >>
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