Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


POST REFLOW BALLING

IAN T

#19129

POST REFLOW BALLING | 13 March, 2002

WE HAVE A PROBLEM WITH SOLDER BALLING POST REFLOW WE ARE RELIABLY DISPENCING HERAEUS PASTE WITH A XY FLEX BUT WE'RE GETTING LARGE BALLS ON THE MELFS AND SMALL BALLS ON MOST CHIP PARTS WHAT SHOULD I BE LOOKING FOR? AND IS PAD DESIGN AN ISSUE (ROUND DOT ON SQUARE PAD?)

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#19136

POST REFLOW BALLING | 13 March, 2002

Nice maCHEEN, mon.

Please explain, �reliably dispensing�. What do you mean? How do measure? How are you sure? Etc.

Just as points of reference: * What is the ratio of height to diameter of your dots? * How are you sure that you�re not stringing? * What is the metal content of your Heraeus paste?

If you are comfortable with your dispensing process, your solder balls are being created like all the rest of the folk, [the just downstream of the paste printer bits only of course]. So, you should search the fine SMTnet Archives for their thoughts on that.

Oh, and you don�t need to YELL, we�re not deaf / blind, yano.

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Alex K.

#19148

POST REFLOW BALLING | 14 March, 2002

Try looking at your reflow profile.

If he slope is too steep you may get solder balls. I've had the same problem, had to slow down the profile a bit.

If you'd like, there was discution on wave soldering chart..

and Speedline one hase some points for reflow as well...

Good luck...

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Reflow Oven