Hi WernerE,

This article certainly minimizes Lead Free implementation.
As a reader it seems like I can pick any alloy and I won't
even have to raise solder temperature very much. Even though
it was an introductory article, they did a disservice by
minimizing analyzing field reliability and reliability
testing.


Gee what ever happened to MSL (Moisture Sensitivity Level)
for components causing difficulty or even making sure your
components were changed to Lead Free, and more.

I am glad you figured out that they were using Dry and then
Wet Thermal Shock to make an "All AOK" Future Reliability
prediction.  Funny 1206 components, which aren't that big
are cracking and they probably didn't do any pin in hole
(pih) components with a small lead in a large hole
(.018).45mm / (.040)1.0mm.

Because I wouldn't expect it, I think I have missed some
presenters using Thermal Shock as their ATC method. Thanks.


YiEngr, MA/NY DDave


<--- Part of Your Note-->
As an example of this, just look in the Circuit Assembly magazine, July
2003, page 25, in "The Cost of Going Green," [we all know by now the going
lead-free is anything but 'Going Green'], where the author Alan Rae,
cookson Electronics, Inc., states under the heading
"What is the reliability compared to eutectic solder?"
We tested reliabilty--air-to-air, liquid-to-liquid--between 550°C and 1250°
C [I would think he meant -55 and 125°C]. We found no major difference
between the alloys and surface finishes, but we did find that large
resistor components (1206) failed frequently due to joint cracking under
thermal stress."
Using thermal  shock tests with no hold times is put forth as proof
that LF-solders are not different than Sn/Pb solders.

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