[tinwhiskers] Re: Should suppliers lead the transition to pure tin?
- From: Steve Smith <smi3th@xxxxxxxxxxxxx>
- To: tinwhiskers@xxxxxxxxxxxxx
- Date: Sun, 6 Apr 2008 14:52:11 -0400 (EDT)
boyoboy talk about telepathy. I was just thinking of you and wondering how
your trip went and was going to email you and saw this in my in-box.
How did the visit with Sununu go?
-----Original Message-----
>From: Bob Landman <rlandman@xxxxxxxxxxxxxxxxx>
>Sent: Apr 6, 2008 2:56 PM
>To: "tinwhiskers@xxxxxxxxxxxxx" <tinwhiskers@xxxxxxxxxxxxx>
>Subject: [tinwhiskers] Should suppliers lead the transition to pure tin?
>
>Lead-Free Zone Blog
>Hi, this is Design News contributing editor, Rob Spiegel. Welcome to my
>Lead-Free Zone blog. This is your opportunity (and mine) to discuss RoHS and
>other environmental issues. Green regulations have produced waves of industry
>confusion, and I do not expect things to clear up quickly. So use this blog to
>inform us of your opinions, to instruct us all on what you're doing about this
>initiative, or just to blow off some steam.
>
>http://www.designnews.com/blog/710000071/post/750022675.html?
>
>Friday, February 29, 2008
>Should suppliers lead the transition to pure tin?
>Feb 29 2008 6:23AM | Permalink | Email this | Comments (0) |
>Blog This! using: Blogger.com | LiveJournal |
>
>
>Design Chain Associates, a company that helps manufacturers cope with
>environmental compliance has released an article from its partner DfR
>Solutions that looks at the state of pure tin in the electronics industry.
>Here's the opening to the article:
>One of the greatest concerns during this transition to Pb-free electronics,
>and therefore Pb-free components, has been the supposed rapid and widespread
>adoption of pure tin plating as the solderability plating of choice. A number
>of questionable surveys have driven this belief, with some promoting that
>'pure' tin has captured 75% or more of the market.
>The response to this wave of tin-whisker susceptible components has been
>impressive. Numerous organizations have sprung up to either analyze (iNEMI,
>E4), inform (ELFNET, GEIA), or fight (NASA Tin Whisker Group) this potential
>reliability threat. Millions have been spent on testing, analysis, report
>writing, and, most importantly, material identification (have you bought stock
>in XRF companies?).
>Why all this time, money, and effort? Because, supposedly, the electronics
>supply chain is backwards. Suppliers call the shots and the OEMs, especially
>those in Hi-Rel (telecom, industrial, military, avionics, medical, etc.), have
>no control over what goes in their product and out to the customer. Could we
>be more wrong? For more of the article, click here:
>http://www.designchainassociates.com/pdf/dfr_tm.pdf
>=============
>I just returned from NASA Goddard Space Flight Center where in their Tin
>Whiskers group, thanks to Henning Leidecker, Jay Brusse and esp. Lyudmyla
>Panashchenko's time lapse 3D photos of growing tin whiskers in a SEM, I saw
>for the first time "live" tin whiskers and zinc whiskers.
>Until you actually see them, unfortunately, most of you will relegate them to
>UFO status. Seeing is believing, sad to say.
>I just read the above article from DfR. It's an interesting argument but it
>lacks completeness as it does not mention passive components such as L/C/R
>parts, tin connectors and other mechanical parts such as shields - all of
>which can grow whiskers and which can come loose and short circuitry or grow
>to 25mm length and short to adjacent components.
>Conformal coatings can mitigate the whiskers that do grow but the problem is
>that the sharp edges on IC leads do not coat well with conformal coatings, so
>I'm advised by NASA, unless the coatings are thickened with, for example,
>cabosil. This is why NASA insists on 3% lead in solder as a minimum and
>expensive XRF testing. I saw a $40K benchtop tester mfg by Fischer that did
>an excellent job of analyzing coatings at their lab as well as a $500K Nikon
>SEM-EDX instrument. It is very unlikely industrial companies will buy SEM-EDX
>instruments.
>Bob Landman
>H&L Instruments,LLC
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