Bob,
Here's a "fist bump" to you!
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| | | ' | |.
| : | | pb | ||
| :. | : | : | : | \
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`-::-'
Steve
----- Original Message -----
From: "Bob Landman" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, January 26, 2009 8:33 PM
Subject: Re: [LF] link to EDN article of possible interest (EOM)
Joe,
This article is full of misinformation. The following is one glaring example:
"For commercial applications, lead-free components are plenty reliable. Tin whiskers are not likely to grow on the components in your cell phone or television. Plus, consumers don't expect a commercial electronic product to last more than a few years. In military and space applications, however, systems have to last decades, facing extreme weather, temperature and vibration."
There is no truth to the statement that only extreme weather, temperature and vibration cause tin whisker growth. How do you explain whiskering in air conditioned computer rooms, in heart pacemakers (FDA recall of a Medtronic device)? The fact is current science does NOT know what causes whiskers to grow; if we did we could experiment with mitigation strategies much more easily. Yes, high temp and humidity seem to accelerate growth but that is not conclusive. I ask each of you - do you expect to throw away your refrigerator, HDTV, automobile, heart pacemaker... "in a few years"? If we are doing this to help the environment, tell me how throw-away electronics is good for the environment? Anyone here for RECYCLING?
The following is a really silly statement:
" "Most companies in the exempt industries are using COTS parts," said Gary Nevison, legislation and environmental affairs manager at Newark. "They're using lead-free components primarily because nothing else is available. But they take additional precautions to ensure high reliability."
One of those additional precautions is dipping lead-free components in lead to enhance reliability."
Dipping parts in lead isn't mitigation, it's remanufacturing! And yes, it's VERY expensive. I find it somewhat good news that Avnet is considering a lead dipping service for it's customers but what will happen to the original part warranty? Because Avnet is an authorized distributor, will they also be an authorized re-manufacturer?
Here's some more nonsense: "Lead was originally added to tin to mitigate the tin whisker problem."
My word, that's news to me! Stop the presses! NO, that is NOT TRUE. Tin-lead is a eutectic connection alloy that works well for conductivity, ductility, and vibration resistance. Tin whiskering was discovered in the 1960s at Bell Telephone in switching centers. Cadmium whiskers were found in radio equipment in WW II.
Still more misstatements:
""People have done a lot of work developing mitigation strategies such as evaluating lead-free finishes that are less of a problem," said Brady. "Plenty of people are spending their careers on this topic." These efforts have met with success, but they tend to be expensive."
There is NO, repeat, NO lead free alloy that eliminates tin whiskering. Use 3% lead if you want to suppress whiskering.
Read the materials at the NASA website (http://nepp.nasa.gov/WHISKER/) - the truth shall set you free (but it will scare the hell out of you).
Sincerely,
Bob Landman, President
Senior Member, IEEE PES, Reliability Society
H&L Instruments, LLC
Electro-Optics for Industry & Science
34 Post Road, PO Box 580
North Hampton, NH 03862-0580
(tel) 603-964-1818 (fax) 603-964-8881
www.hlinstruments.com
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of Joe Fjelstad
Sent: Monday, January 26, 2009 6:36 PM
To: [log in to unmask]
Subject: [LF] link to EDN article of possible interest (EOM)
http://www.edn.com/article/CA6630671.html?nid=3351&rid=1549644147
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