WE have to resort to special component purchases specifying no pure tin and
have had to add the expense of testing to confirm we got what we ordered.
We have already experienced surprises and unintentional intrusion of pure
tin components into some of our Hi-Rel assemblies.  The discovery and
resultant rework and re-qualification have been/still are a nightmare.  Some
parts can be used by careful pre-tinning (what a contradiction of terms)
with SN63 in a solder pot.  That is difficult because getting all the pure
tin to alloy means getting right up to the body.  In some cases, application
of conformal coating has been the mitigating response for less than 100%
alloying.

> Rainer G. Blomberg
> Honeywell -Space Systems Clearwater
> Staff Production Engineer
(727) 539-5534


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bloomquist, Ken
Sent: Thursday, November 17, 2005 11:48 AM
To: [log in to unmask]
Subject: [TN] Pure Tin Component Lead Plating

There's been enough discussion over the past couple years about "tin
whiskers" to choke a horse but...

I'm curious what the high rel, aerospace and medical people are doing as
component manufacturers transition to lead free and end up using pure tin as
a lead finish?

There will soon come a time when you can no longer buy SnPb components and
if the component manufacturers switch to pure tin as their alternative what
will we do? What are you doing?

Thanks in anticipation of some great replies,

KennyB

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