Mornin Steve -

The ramp rate is generally governed by the what the components will
withstand.  If necessary to remain in this window, then the question
becomes, "Will the flux remain viable for the longer preheat cycle?"  You
need your paste manufacturers guidance to help on that one.

Sn96 doesn't produce the prettiest solder joints in the world, so you might
as well get your Quality folks prepared ahead of time.  If the boards happen
to be coated with a more or less eutectic solder or fused tin/lead plate,
then the joints become even uglier, and turn out to be an amalgam of both
alloys.

Good luck - Kelly
-----Original Message-----
From: Stephen R. Gregory <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Thursday, December 16, 1999 5:51 PM
Subject: [TN] Reflow profiles with SN96 solder


Hi ya'll!

Most all my reflow profiling experience has been with the typical Sn63Pb37
alloys. But we'll be getting some products in here later on that will
require
that we use a SN96AG04 alloy (they're boards that go into oil well drill
head
instumentation, hot stuff down there!) Liquidous will be up around 221-229º
C.

So should I follow the same rules of thumb when it comes creating a profile
for this stuff...ya' know; don't ramp more than 2-4º C per second, pre-heat
and soak above 150º C for around a minute and a half, then spike it until
you're 20-30º above liquidous, and try to be less than a minute while you're
above liquidous? Or is there some special stuff I should do differently with
this higher melting point temperature alloy?

'preciate it!

-Steve Gregory-

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