Please foward this message to it's appropriate location.

Our company has been manufacturing a double-sided SMD pcb using an IR
solder process.  We have been using the same no clean solderpaste for
the last few years.  Recently we changed pcb vendors for cost reasons,
and the new boards seem to have a higher degree of solder flux residue
migration.  

The problem we have is with the hardened flux on the testpoints and the
difficulty in penetrating it consistantly.  The only difference in the
pcb's from the new source is in the soldermask.  The new boards have a
Hysol screened Wet mask that has a rough texture to it.  The previos
boards had a LPI soldermask that was glossy and smooth in texture.

My question is, why would the difference in soldermask applications
cause a higher rate of solder flux residue migration?  Any insight at
all would be greatly appreciated.  Thank you.

Eric L. Johnson
Sr. PC Designer
Nartron Corp.
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