To: "Kelly, Pat" <[log in to unmask]>


We have had problems with tin plated parts loosing their solderability
after extended time in stock.  Occasionally we have to send them out to
be hot tin dipped to renew their solderability.  I have no experience with
your particular fasteners... but you may want to look at the shelf life
after the tin plating.  Tin plating may be somewhat porus and allow oxidation
to occur that will hurt solderability.  Your parts may have passed the
solderability test when first manufactured.  You did not state in your note
whether or not you retested fasteners from the lot of parts that had the
problem.



At 04:51 PM 7/31/96 -0400, you wrote:
>:
>:
>: ----------
>:From: Kelly, Pat
>:To: Technet
>:Subject: Wave solder not adhering to electrotin plated fasteners
>:Date: Wednesday, July 31, 1996 3:52PM
>:
>:Hi there!
>:
>:I need some help.  We manufacture steel, threaded fasteners that broach into 
>:printed circuit boards.  These fasteners are electrotin plated for excellent 
>:solderability.  These fasteners pass the ASTM B678 solderability test 
>:easily.
>:
>:One customer is using our fasteners in a typical PCB application.  After 
>:installing our fasteners, the board is put thru a wave solder process.  This 
>:customer claims - and has given me samples - of fasteners that definitely 
>:have not held soldered adequately.
>:
>:Anyone out there please help.  Why would our fasteners pass the ASTM B678 
>:solderability test but experience trouble in a "real world" application? 
>: Has anyone experienced a similar problem with our fasteners.  Let me know.
>:
>:
>:Thanks,
>:
>:Pat Kelly
>:Applications Engineering Manager
>:Penn Engineering
>:215-766-8853-1162
>:[log in to unmask]
>:
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Bill Dieffenbacher,  Lockheed Martin Control Systems
[log in to unmask]  Phone 607-770-2961  Fax 2056
_______________________________________________________________

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