*"The investigation led to the conclusion that tin plating on electronics
components had grown "whiskers.""*
NASA with the big budget projects can find in the market Tin-Lead plating
on "electronics components" for their circuits...
Reuven
On Tue, Mar 20, 2012 at 8:50 PM, Stadem, Richard D. <
[log in to unmask]> wrote:
> Tin whiskers can grow in leaded circuits, ie, CCAs soldered with Sn63. The
> issue is that the parts need to be tinned of their lead-free original
> finish, and the ENTIRE LEAD then must be tinned with Sn63. If you leave a
> portion of a SAC305-finished lead untinned, the line of demarcation between
> the Sn63 solder and the SAC305 is a fertile garden for the growth of tin
> whiskers.
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Joyce Koo
> Sent: Tuesday, March 20, 2012 12:57 PM
> To: [log in to unmask]
> Subject: Re: [TN] Out of the world tin whiskers
>
> I thought space is exempt for leadfree. Why?
> --------------------------
> Sent using BlackBerry
>
>
> ----- Original Message -----
> From: Inge Hernefjord [mailto:[log in to unmask]]
> Sent: Tuesday, March 20, 2012 01:47 PM
> To: [log in to unmask] <[log in to unmask]>
> Subject: Re: [TN] Out of the world tin whiskers
>
> DO THEY NEVER LEARN!
>
> Inge
>
> On 20 March 2012 18:08, Gervascio, Thomas L <[log in to unmask]
> >wrote:
>
> > Tin whiskers at Saturn
> >
> > PASADENA, Calif. -- The Cassini plasma spectrometer instrument (CAPS)
> > aboard NASA's Cassini spacecraft at Saturn has resumed operations.
> Mission
> > managers received confirmation on Friday, March 16, that it was turned
> on.
> > They plan to monitor the instrument for any unusual behavior.
> > Last June, short circuits in the instrument led to unexpected voltage
> > shifts on the spacecraft. As a precaution, mission managers turned off
> the
> > CAPS instrument while engineers investigated the issue. The investigation
> > led to the conclusion that tin plating on electronics components had
> grown
> > "whiskers." The whiskers were very small, less than the diameter of a
> human
> > hair, but they were big enough to contact another conducting surface and
> > carry electrical current. Researchers are still trying to understand why
> > whiskers grow on tin and other metals, but they know now that whiskers
> can
> > grow in space and on Earth. It is believed that these or additional tin
> > whiskers that may grow on Cassini cannot carry enough current to cause
> > problems, but will burn out on their own like a lightweight fuse.
> >
> >
> >
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--
Best Regards,
*Reuven Rokah*
Mobile: 972-52-60-120-18
Tele-fax: 97239360688
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