Hi Jonathan!

I've posted your image on my web site. It's at:

http://stevezeva.homestead.com/index.html

and then click on Oven Diagram....

It's a basic diagram of your reflow oven. I think there are questions that
others may have, such as:

Is the "other" oven that reflows fine, the same as the one that you see the
problem with?

What is it that you are reflowing at such a high temperature? Devices, or
printed circuit assemblies?

What you are referring to as "Heater blocks" in your drawing, are they
radiant heaters, ceramic heaters maybe?

May the force be with you...you are dealing with some extreme stuff...

I have a question though, what kind of profiling equipment do you use that
can withstand that kind of heat?

Sorry, I can't help much...

-Steve Gregory-

Hello Friends,

Can anybody explain why there is always a non-reflow of solder paste as
shown by the drawing below?

(Embedded image moved to file: pic07711.pcx)

The solder paste used for assembly was 88Pb10Sn2Ag and it is an Indium No
clean paste. Its liquidus temp was 290 C and solidus temp of 268 C.

Reflow Atmosphere: N2 purge as hot gas and cool gas (shown at the above
drawing) although we tried to increase the temp to over than 300 C, it is
still the
same results.

I tried the paste to other oven with a forming gas blanket, and reflow it
to a peak of 295 C the results were good (All reflowed).

We had profiled the above oven at 3 points Left edge, Midle and. Right edge
and temperature difference vs setting was ą 5 degree C on that three points.

Was the non-reflow due to the blanket? O2 ppm level? But why on the left
side only?

Does a localized heating have occured? But the temp profile was okay?

Do you have any insights that you can share?

God Bless You All...
Thanks