Hi folks! Rockwell Collins will be presenting the ongoing (3 years +)
status on tin pest of solder joints at the SMTAI Conference in August
which will help address some of the concerns folks have voiced. I echo
Keith's comments - we should be concerned and conduct further
investigations but the sky isn't falling yet. The tin pest results and
testing protocols that Dr. Chris Hunt (NPL), recently published will
enable the industry to acquire a better understanding of the tin pest
transformation mechanisms which should go a long way in assessing how tin
pest would impact a solder joint.
Dave Hillman
Rockwell Collins
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Sent by: Leadfree <[log in to unmask]>
07/18/2008 06:46 AM
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Re: [LF] Tin Pest Caught in the Act
Hi Werner,
Tin pest has come and gone as issue over the past century or so but as far
as
I can tell it was a picture of some SnCu alloy tensile test pieces that
the
Open University's Professor Plumridge included in a paper that put it on
the
agenda as far as Pb-free is concerned. Those test pieces were covered
with the
"warts" that first prompted the description of the phenomenon as a "pest",
i.e. disease or pestilence and certainly looked very frightening to people
concerned about the integrity of their solder joints at sub-zero
temperatures.
From then on that image started appearing in papers and presentations by
those
who held "the sky is falling" view on lead-free implementation.
I have always suspected that those test pieces had been made with 99.99%
grade tin, or certainly tin with a very low level of lead but as far as I
know
that has never been confirmed or denied.
Keith Sweatman
Nihon Superior Co., Ltd.
In a message dated 18/07/2008 3:31:16 PM E. Australia Standard Time,
[log in to unmask] writes:
> Subj:Re: [LF] Tin Pest Caught in the Act
> Date:18/07/2008 3:31:16 PM E. Australia Standard Time
> From:[log in to unmask]
> Reply-to:[log in to unmask]
> To:[log in to unmask]
> Sent from the Internet ()
>
>
>
> Hi Keith,
> Thanks for the input?I briefly talk about tin pest in my new workshop in
> Pb-free. However, I cannot cite a single incident where tin pest had any
role
> ?
> where and why has this concern arisen?
>
> Werner Engelmaier
> Future workshops:
> Solder Joint Reliability: Parts 1 through 4, July 17/18, Thal,
Switzerland
> Pb-Free Soldering Processes?Survival, Quality, Reliability, August 18,
> Orlando
> Reliability Issues with Lead-Free Soldering Processes, September 22,
> Schaumburg
> Failure Mode and Root Cause Analyses Reliability (Fatigue, Brittle
Fracture,
>
> ENIG), September 22, Schaumburg
> Solder Joint Reliability: Parts 1 & 4, Oct. 9, Moscow, Russia
> Solder Joint Reliability: Parts 1 & 4, Oct. 22, Tallinn, Estonia
>
>
>
> **************
> Get fantasy football with free live scoring. Sign up for
> FanHouse Fantasy Football today.
>
> (http://www.fanhouse.com/fantasyaffair?ncid=aolspr00050000000020)
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>
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