Jack,
I'd be surprised if your board supplier was really paying attention to
that.. I mean does anyone have a HASL machine set up with Sn70 solder? You
probably got Sn63..the standard HASL solder.
Also, the liquidus for Sn70 is only 378 deg C (vs. 361 deg C for Sn63). It
doesn't seem like that would stay solid in your selective soldering process
without very tight temp. control.
Tim Reeves

> ----------
> From:         Jack Olson
> Sent:         Thursday, October 14, 1999 5:34 PM
> Subject:      Tin content of HASL
>
> I've just noticed that our fab notes call for 70% Tin 30% Lead on Hot Air
> Solder Level.
> This only struck me as odd because at a previous company we used SN70 as a
> high temperature solder (I think) for terminal posts, so it wouldn't
> reflow
> when we soldered wires to it using SN60 or SN63.
>
> Is it more appropriate to use SN60 or SN63 for HASL?
>
> Is there some advantage to using SN70?
>
> (Sorry for the cross-posts, but this affects FAB and ASSY as well as
> DESIGN)
>
> Thanks in advance,  Jack
>

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