Charles Barker@IO-US
11/13/97 08:58 AM

Hi Karla,

Here is something I forgot to ask that you might check:
What is your top side temperature just prior to hitting the wave?

We experienced similar problems a while back and found that the guys were
running the conveyor way too fast. The Engineer who sorked on solving that
problem remembers that the SOT's soldered much better when he got the top
side temp to reach about 200 deg F prior to hitting the wave. That involved
careful setting of the bottom side preheaters and the speed for a proper
thermal profile. He found that it was best not to use top side preheat.
Your settings of 3.25 fpm and 500 degs sounds about right, but I don't know
about your preheat set up.

As Mr. Engelmaier said in his posting, the alloy in the SOT leads is more
sensitive to lack of heat than most other critters' leads.

Good luck,

Charlie B.




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