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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