Dave and all - One problem will be to determine a "standard" alloy to use
for solderability testing. Using 63/37 or 60/40 Sn/Pb alloys has always
been the standard. With the plethora of proposed alternative alloys (there
are already over 120 patents just in the USA and Japan) what will be the
standard. Maybe for simplicity SnAg or SnCu or SnAgCu eutectics should be
used at an appropriate temperature of, say, 260°C. Just some thoughts.
-----Original Message-----
From: David Hillman [mailto:[log in to unmask]]
Sent: Friday, August 27, 1999 3:36 PM
To: [log in to unmask]
Subject: Re: [LF] Solderability standards
Hi Bob! Sorry but I'm a non-believer - there is a very dedicated group of
industry folks who have been working very hard for quite some time and the
"we don't have enough time" is a very real, legitimate statement in terms
of a lead-free solder alloy implementation (that's enough soapboxing for me
today). The ANSIJ-STD-002A and 003 IPC/EIA solderability committees have
been working very hard on addressing the possibility of lead-free solder
alloy implementation. The committees are currently working on revising the
specification flux requirements, have addressed the solder test temperature
for the current alloy situation, and are working on changes in how
accelerated conditioning should be altered. Several of the 002A and 003
committees are participating in the NEMI lead-free component lead finish
task group and one committee member is currently at day 450+ on a shelf
life board finish degradation study. The solderability committees are very
active in the trying to understand the implications of lead-free solder
alloys and will be very willing to assist in proactive, logical efforts to
eliminate lead. One paper of interest is "An examination of the shelf life
of 5 solderable coatings in real time using a wetting balance", Gerard
OBrian, AESF SurFin 99 Session D,G, K, & P Technical Conference
Proceedings, pages 423-450.
Dave Hillman
CoChair JSTD-002/003 committee
[log in to unmask]
"Martel, Robert" <[log in to unmask]> on 08/27/99 12:00:18 PM
Please respond to "Leadfree Electronics Assembly E-Mail Forum."
<[log in to unmask]>; Please respond to "Martel, Robert"
<[log in to unmask]>
To: [log in to unmask]
cc:
Subject: [LF] Solderability standards
The last 50 or so E-mails underscore my original point - time spent
debating
is time NOT spent finding a solution! So again, please don't use the "we
don't have enough time" excuse for not getting ready for these lead-free
initiatives. There has been ample time to get ready, but for whatever the
reason, many have chosen not to, perhaps hedging their bets that this whole
thing would just blow over. Having to scramble now is the price to pay for
losing that bet.
I for one would like to see this forum re-focus on finding solutions!!
Perhaps another E-mail forum could be started with more of a "Lead-free
Soap
Box" theme?
Along those lines, does anyone know of a standard for doing solderability
testing on lead-free packages? Mil-Std-883, Methods 2003 and 2022 are what
we always used in the past. However, those both call for a Sn/Pb solder
dip. It doesn't make much sense to characterize a lead-free package using
a
leaded solder dipping process, since any customer who would ask for a
lead-free package is almost certainly not going to be using lead on their
PCB. Any pointers or suggestions would be greatly appreciated.
Best regards,
Bob
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IPCWorks -October 25-28 featuring an International Summit on Lead-Free Electronic
Assemblies.
Please visit IPC's Center for Lead-Free Electronics Assembly
(http://www.leadfree.org ) for additional information.
For technical support contact Gayatri Sardeshpande [log in to unmask] or 847-790-5365.
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