I agree Steve,
That is very old technology and if there is large ground plane areas the
tin lead or solder will re-reflow and will cause yet more trouble for
the assembly people

Highest Regards
William W. DeCray III
Sales Engineering Manager
Waytec Electronics Corp.
Phone: (434) 237-6391 Ext 115
Fax:   (434) 237-1324
Cell:  (434) 851-6115
E-mail [log in to unmask]
Website www.waytec.com


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Wednesday, March 31, 2004 4:41 PM
To: [log in to unmask]
Subject: [TN] Solder mask over Tin/Lead...

Hi All!

I'm just wondering if I'm missing something. Is there any performance
reason
whatsoever, that requires solder mask over Tin/Lead instead of using
SMOBC
(Solder Mask Over Bare Copper)?

Got a board in receiving inspection that I got called back to look at
because
the mask was failing tape test. When I saw the board, it was solder mask
over
Tin/Lead, just like it was called out on the drawing. The mask had
already
lost adhesion in a few places, but we hadn't done anything to it yet
assembly-wise...

I see didn't see this particular boards drawing before we went out and
bought
it, otherwise I would have thrown-up a red flag then. What suprised me
though, is that our fab vendor didn't say anything before they built it.
Is anything
other than SMOBC being used regularly. I thought solder mask over
Tin/Lead
was ancient stuff, and that everybody learned not to do that anymore...

-Steve Gregory-

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