Par.6.5.2. of IPC-A-610C:
Acceptable-Class 1,2,3
-Exposed copper on vertical conductor edges
-Exposed basis metal at ends of component leads
But... The picture shows exposed copper alloy of lead base matrial.
What's the catch???
Gaby

> ----------
> From:         Rick Howieson[SMTP:[log in to unmask]]
> Reply To:     TechNet E-Mail Forum.;Rick Howieson
> Sent:         ?יום שני 29 ינואר 2001? 16:33
> To:   [log in to unmask]
> Subject:      Re: [TN] fractured joints
> 
> Careful Doug...nowhere does the spec indicate trimmed leads must be
> covered
> with solder. An example, how would YOU explain the acceptability of an
> exposed vertical trace on a board that has been SnPb plated and fused?
> Rick
> 
> -----Original Message-----
> From: Douglas Pauls [mailto:[log in to unmask]]
> Sent: Monday, January 29, 2001 7:01 AM
> To: [log in to unmask]
> Subject: Re: [TN] fractured joints
> 
> 
> The IPC standard states that all clipped leads must either be  reflowed or
> checked under 10X magnification. Is this just a standard for single  sided
> boards? If you have a double sided board and a good fillet on the
> component side of the board and you clipped the leads on the solder side
> what  would be the cause of concern if a joint is fractured on the solder
> side?
> 
> *One of the reasons that the specifications want you to check the clipped
> leads, or better yet, reflow the solder to cover the clipped lead is so
> that you cover the exposed metal of the lead which may corrode.  I have
> seen many cases where a ferrous core of the lead is exposed by the
> clipping
> process, which then corrodes in service.  If that exposed metal was
> covered
> with tin-lead, that corrosion does not occur.
> 
> Not quite what you were looking for, but something to think about.
> 
> Doug Pauls
> Rockwell Collins
> 
> 
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