Very well put Mr. Landman!
I don't understand the last paragraph...
" Many in the component industry believe the difficulty in finding
reasonably priced, high-reliability parts will eventually be solved with
lead-free parts. At some point companies will view lead-free parts are
sufficiently tested and reliable. "People are gaining confidence in
lead-free components," said Brady.
That confidence is likely to grow as component manufacturers gain more
experience in producing lead-free parts. "I think lead-free components
will continue to improve," Brady continued. "For most of our customers,
lead-free is no longer an issue."
Am I missing something here, because I am still concerned?
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of Bob Landman
Sent: Monday, January 26, 2009 8:33 PM
To: [log in to unmask]
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
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