Pratap do you work in electronics?
John
John Burke
(408) 515 4992
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of Pratap Singh
Sent: Tuesday, December 05, 2006 7:21 PM
To: [log in to unmask]
Subject: Re: [LF] JCAA/JGPP Lead-Free Solder Project summary
Werner,
I am really disappointed that a person of your experience and background is
on anti-LF band wagon. You are taking a position that does not go with the
test data and field observations being generated by LF products being
shipped around the world for the last 5 years.
Here is some of what people are saying:
"There are now more than 2000 lines around the world running SN100C some
since 1999 with more than 500 million boards in service and so far no in
service reliability issues have come to our attention.
K. Sweatman, Nihon Superior Co. Ltd."
"There is no doubt that we are still on the learning curve as far as Q&R is
concerned. However, as you know from events where hard data is being sliced
and diced in the public eye, there is tremendous progress being done in
that area. There has not been massive generalized failures thus far, that I
am aware of. There will definitely be issues in applications where
workmanship requirements and design-for-reliability principles are violated.
But then again, we have had similar problems with SnPb assemblies for many
years. I get a few of those land on my desk on a regular basis, including
on products used in mild environments. It always boils down to minimal or
poor joint quality and/or insufficient-to-total lack of
design-for-reliability." Dr Jean-Paul Clech, email dated 12/5/06 on this
forum.
If you do not agree with these statements, it is OK with me, I will not say
that you are wrong but simply that is your opinion. Time will tell what
happens to LF product in the field over the next 5 year. What data I have
seen so far and read about it in publications, the Sky is not falling.
As part of a team at IBM, we implemented LF solder on a 22 inch x 24 inch 22
layer PCB with 0.016 drilled PTHs (30,000 count) and used that board in main
frame computers. The field failure rate of solder joint was as a matter fact
lower than previous technology that used SnPb product for 360 series system.
Last year, I had the opportunity to develop a LF soldering process (using
Indium alloy 182) for a project at University of Texas, Austin. SnPb was not
used because it could not provide enough joint strength for ZrCu bus bars
that were soldered to a BeCu current distribution disk. The
electro-mechanical assembly (a propulsion motor) weighed almost 750 lbs and
each bus was passing 1000 amps. This application is an example of very high
rotational stresses and electrical loading. Long live LF.
Have a good day.
pratap singh
____________________________________
Tel/Fax: 512-255-6820; Cell: 512-663-8903
www.rampinc.com ; EMail: [log in to unmask]
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