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In a message dated 5/25/99 8:22:18 AM Pacific Daylight Time,
[log in to unmask] writes:
<< Sorry but if our Electronic Times is telling the truth the IPC is
intending to encourage lead free products in the U.S. along with Europe.
It appears the requests for the IPC to oppose the European legislation
have brought the whole thing about.
Looks like we might all be ending up with the lead problem. I wonder
what the new definition for solder will be in a few years time.
--
Roger M Unwin
P+M Services (R) Ltd. Tel: 01706 815212 Fax: 01706 818636
Http://www.p-m-services.demon.co.uk >>
Hi Roger!
You've started-up once again one of my favorite (?) topics. But I don't think
what you've read is quite correct...that is unless things have change
drastically in the last few weeks. While not attempting to speak directly for
the IPC, I do have the May 1999 copy of the magazine "IPC Review" and it
contains a very good article about the push for Lead-free, and the forum that
was held at the IPC Printed Circuits Expo '99; "Getting the Lead Out of
Electronics: Is it Feasible, or Even Warranted?" The subtitle of the article
is; "Tension over lead is building again. But is the cure more painful than
the disease?" Doesn't sound something one would publish if they're ready to
roll over and push for lead free does it?
A few salient points from the article:
"Even before the forum began, a straw poll of about 100 PWB executives
meeting in another corner of the Expo indicated that 70 to 80 percent of the
boards they build are produced with hot air solder leveling. Lead based
solders have been the one constant in assembly for decades. And how many
components have no-lead leads?"
"The forum itself was a potpourri of data. A four year, $10 million study
funded by several major US OEMs and the National Institute of Standards and
Technology and conducted under the auspices of the National Center for
Manufacturing Sciences found that, among 79 alloys researched, only three
were suitable as lead alternatives, and none were drop-in replacements."
"In research begun as part of a U.K consortium in 1992, 200 solder alloys
were evaluated, with seven ultimately selected for trials, and two -
tin/copper and tin/silver - settled on for detailed analysis on performance,
cost and availability. These alloys were tested with various component and
PWB finishes. Consortium members Nortel Networks and Cemco explained that
temperatures of tin/copper HASL are uniformly higher than tin/lead; for
example, air knife and bath temperatures of the former are 280° C. And pull
strength tests showed tin/copper to be slightly weaker than tin/lead,
although it did do better in multiple pass reflow and high humidity aging
tests run with gold over nickel finishes."
And the final point of the article that I like:
"With the scientific merits at best ambiguous, the price of a lead-free
electronics world is high."
-Steve Gregory-
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