Thanks so much, Steve, for sharing this vital information.
This is the first I've heard of this recall. I noted that Tyco didn't title this document as a RECALL but that's what it clearly is.
IMHO, tin plated anything is to be avoided at all costs as there's no such thing as a whisker-free tin plating. NASA has seen them on USB connectors. http://nepp.nasa.gov/whisker/photos/index.html No component manufacturer who has made such claims has backed it up with proof we can trust.
If you read their claims very carefully you see the legal department's help craft their statements. Real proof, as we see in this sad case, takes YEARS, not iNEMI's 4000 hour test (which allows whiskers as long as 50 microns) proves.
What are we manufacturers to do?
The iNEMI JESD "standard test" gives false hope to us consumers. It was the lowest bar all apparently could agree to. What good are claims of any manufacturer if production can make this kind of mistake?
Wouldn't you like to know how Tyco let this mistake go on for years 2005-2010 and why was it only customers detected the whiskers?
(We use a more expensive 3M part which is gold over nickel over copper, thank goodness!)
Tyco is kidding itself (and the consumers) when it says in the announcement: "may have a higher than normal risk of developing tin whiskers". I'd like Tyco to tell us exactly what is a "normal risk of developing tin whiskers"?
Rohm & Hass markets a tin plating solution called "solderon ST-380" which it claims: "provides a deposit with low whisker propensity". If that's true, then why doesn't Tyco use it? Why (in its revised manufacturing spec) does Tyco not allow tin on the area of the connector that is subjected to compressive stress?
There are no lot codes on these parts. Even if there were, how many manufacturers track lot numbers in their bills of material? It would be a logistical nightmare. If they are still in stock (this is unlikely), then they can be pulled but once they go into a product, that door is closed forever.
There is no way to find and replace the installed connectors that are affected in this recall. How many products are already failing? Have there been fatalities?
AIA-PERM has released a whitepaper on the subject recently which states:
"The technical knowledge and data necessary to perform quantitative reliability assessments for ADHP lead-free electronic systems do not yet exist. Based on our current state of technical understanding, the Steering Committee concludes that the
aerospace, defense and high performance electronics industries do not presently have the technical knowledge or data necessary to provide a level of confidence in reliability assessments for lead-free electronics equal to that currently available for traditional tinlead electronics. It is premature to rely solely on MIL-STD-810, MIL-HDBK-217, and RTCA DO-160 for qualification of systems containing lead-free assemblies in critical, high-reliability, harsh environment
applications without rigorous assessment of application requirements."
Dave Hillman was recently interviewed by Terry Costlow stating:
The growths, which occur on components that use plated tin surface finishes, are a bit more shrouded in mystery than most issues in soldering processes. Whiskers usually don't occur until well after manufacturing is completed, and it's problematic to predict when they'll grow. It's difficult to figure out whether or not they will show up, making them especially vexing in high reliability applications like the military or automotive.
"Tin whiskers don't just have one or two causes. A lot of things set them off," said Dave Hillman, principal materials and process engineer at Rockwell Collins. "We know that stress is a primary driver, but there are still a lot of questions about what causes them."
Though it's difficult to tell what causes tin whiskers, their impact can be significant. Short circuits are a common problem. Some researchers feel that the metallic growths may be overlooked since they can fall off when the board is being sent to technicians who examine it to see what's happened. "The real question is 'how real is the tin whiskers effect?' When you have a failure mechanism, but we don't know its root cause, it's difficult to fix," Hillman said.
Mystery? We have to obey stupid EU RoHS laws that result in mystery?
Hans Christian Anderson wrote a childrens story that is very apropos, perhaps you heard of it?
"The Emperor's New Clothes" http://www.youtube.com/watch?v=-ZYzbkk5X4M
Bob Landman
H&L Instruments, LLC
www.hlinstruments.com
LDF Coatings, LLC
www.ldfcoatings.com
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bush, Jeffrey D. (US SSA)
Sent: Friday, November 19, 2010 10:38 AM
To: [log in to unmask]
Subject: Re: [TN] Tin strikes again!
It is quite amazing how many components have been switched to >95% tin without notification and change of part numbers. Without a disciplined parts pedigree program many contractors have expended major resources on mitigation for PMP issues. This issues are more common than most believe and additional events are uncovered against legacy safeguards for whisker prevention.
Jeffrey Bush
Sr. Principle Product Assurance Engineer Space Products and Systems - Performance Excellence BAE SYSTEMS P.O. Box 868, MER24-116A Nashua, NH 03061-0868
Facility: 144 DW Highway
Merrimack, NH 03054
Office +1 603.885.8137
Mobile +1 603.318.8056
Fax +1 603.885.5258
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Friday, November 19, 2010 10:16 AM
To: [log in to unmask]
Subject: [TN] Tin strikes again!
Morning all!
Before I post the Quiz pictures today, I got something from one of my friends back in Tulsa that might interest you if you haven't seen it:
http://stevezeva.homestead.com/Tyco_Letter.pdf
Tin strikes again!
While we're on the subject of whiskers, here are some Inge's more spectacular whisker images from a while back:
http://stevezeva.homestead.com/files/daniel121b.jpg
http://stevezeva.homestead.com/files/daniel131b.jpg
http://stevezeva.homestead.com/files/daniel141b.jpg
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