Well, it stripped out the "cut and paste" from the pdf of Jasbir's slide at
IPC.  Here is what he said on the slide:


During rework with SnAgCu alloy with copper from the PCB: copper dissolves
with increasing contact time.

Experience: PTH barrel knee erosion after  20 seconds of solder pot dwell time

Copper dissolution is a function of  original barrel/pad thickness, solder
temperature and alloy (tin percentage),  dwell/contact time and solder flow rate
and type of copper plating.

Studies are ongoing with dissolution rate comparison with various  lead-free
solder alloys and process optimization.


Denny Fritz

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