Pratap,
What about the environmental issues with lead-free solders? Do you have any
opinion about that?
-Steve Gregory-
----- Original Message -----
From: "Pratap Singh" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, December 05, 2006 9:21 PM
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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--------------------------------------------------------------------------------
Hi Pratap,
I cannot help but correct you on a number of misconceptions.
You state:
> Several papers on LF reliability and comparison with SnPb joints by people
> like Dr. John-Paul Clech, Dr Craig Hillman, K. Sweatman of Nihon Superior
> and others have stated these observations.
> 1. LF is better than SnPb when stresses are low and medium intensity.
( A large majority of product applications fall in this category)
2. Under highly stressed conditions like aviation, SnPb joints are
better LF joints.
A: I know all of these people and they would never make such a statement in
terms of product reliability, but only in terms of accelerated test
resultsā?"
this in not the same thing by any stretch of the imagination.
> Dell has shipped > 30 million LF
> products of various types (notebooks, Desktops, Displays and Printers) as
> mentioned by Dr. Randy Schueller. These products are performing as well as
> SnPb products or better according to him (November 2006 CTEA presentation
> at
> Austin, Texas).
> A: Wrong, there are laptop computers failing because of solder joint
failures.
>
> No body is being forced to go LF. It is a simple business decision; if one
> wants to play in global economy then one has to follow what the customer
> (an
> individual, a company or a country) wants. If US companies think LF is not
> in their interest, they can continue SnPb production and simply sell the
> product in US market only and not in EU.
> A: Wrong, of course you are forced to go LF--otherwise you are out of
business; just look at the SWATCH product that they could not procuse with
LF.
...and have you really thought about what you are saying in the last
sentence; I
don't think so!
Werner
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To unsubscribe, send a message to [log in to unmask] with following text in
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To temporarily stop/(start) delivery of Leadree for vacation breaks send:
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847-615-7100 ext.2815
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To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Leadfree
To temporarily stop/(start) delivery of Leadree for vacation breaks send: SET Leadfree NOMAIL/(MAIL)
Search previous postings at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
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