Hi Leland! Unfortunately the industry is going to need some time to develop
the wave solder pot impurity level table you are seeking. A fair portion of
the industry is using the current JSTD-001 impurity level table (user
modified for the increased tin, silver, and copper levels) and closely
monitoring their impurity levels. I would recommend that you work closely
with your solder supplier as they have visibility into the status/trends of
existing wave solder processes to whom they supply solder. Here is a
relevant reference on some wave solder impurity levels that may be of
interest:
“Development and Validation of LeadFree Wave Soldering Process”, A. Forsten
etal, Soldering & Surface Mount Technology, Vol. 12, No. 3, 2000
The short term solution is that the industry just needs time to understand
the potential changes to the JSTD-001 impurity limits that Pbfree solder
usage may induce. Good Luck.
Dave Hillman
Rockwell Collins
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Leland Woodall
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INC.COM> To
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01/21/2005 05:26 [TN] Lead-free Wave Solder Pot
AM Impurity Levels
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Leland Woodall
<lwoodall@CSTECH-
INC.COM>
Hi Folks,
I have a small dilemma here. There is a standard for eutectic solder pot
impurity levels, but I can't seem to find one for lead-free. Is there
such an animal?
Everything I've researched on the Web shows only recommendations, namely
from Alpha and AIM. Those two have slight disagreements.
At least they provide something, and that is impressive.
It also appears that the major concern is processing problems versus
product reliability. If copper content gets too high, the wave solder
viscosity becomes too high and bogs down the mechanical parts of the
machine.
When things get out of whack, can I expect reliability problems as well?
What levels of impurities would cause premature joint failure,
specifically?
Are we too new to this, and have tests not yet been agreed upon? Is IPC
addressing the issue?
Any help you could provide would be sincerely appreciated.
Offline comments are welcomed.
Many, many thanks,
Leland Woodall
Quality Coordinator
Keihin Carolina System Technology, Inc.
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