Ramon,
We are developing a method to remove the intermetallics in the HASL process
and it should work for any molten solder pot. The key is the copper/tin has
a higher melting point so we can get it to preferentially solidify in a
controlled area for easy removal.
For a flat bottom pot, it is as easy as cooling the solder to just above the
melting point (SAC-225C, SN100C-232C) and scrapping the bottom of the pot.
    The very best way to eliminate this issue is to use a lead free alloy
which dissolves copper slower than the SAC alloys. SN100C copper dissolution
is up to 4 times slower than SAC and we have never had to have a pot diluted
to keep the copper within our recommended maximum of 0.85%.

Regards,
Bob

----- Original Message -----
From: "Dehoyos, Ramon" <[log in to unmask]>
To: "TechNet E-Mail Forum" <[log in to unmask]>; "Bob Gilbert"
<[log in to unmask]>
Sent: Friday, July 08, 2005 10:43 AM
Subject: RE: [TN] LF Selective and Wave Soldering



Hi Bob:
What is the option? To empty the pot when it is not of the right
mix? Or is there a way to remove the intermetalics?
Regards,
Ramon

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bob Gilbert
Sent: Friday, July 08, 2005 10:55 AM
To: [log in to unmask]
Subject: Re: [TN] LF Selective and Wave Soldering

Hi Dennis,
The best way to control the copper level is to have the pot checked on a
regular basis. You will need to check it more frequently anyway as this
will be your method to certify joints made as being lead free for RoHS.
We offer our customers free analysis as part of our SN100C guarantee
program.

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