Try a home plate or reverse home plate stencil aperture.

http://www.alphametals.com/leadfree/pdfs/Optimizing%20Stencil%20Desing%20for%20Lead-Free%20Processing%20(SMTA%202004).pdf

Karen Tellefsen - Electrical Testing
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908-791-3069



We recently received a call from one of our customers that their boards
are failing Hi-Pot test.  They sent us a picture of a solder ball under
one of the chip caps (package 1825).  Apparently it's present on all 50
boards we built and always in the same place.  We are using leaded paste
for this build and the stencil we received was from the previous
manufacture who could not fix the problem and went to hand soldering the
part (info we got after the fact).  I have inspected the stencil and it
looks fine.  The apertures are a 1:1, so the only thing I can think of
is getting a reduction of some kind on the stencil.  I will send the
picture to Steve to get it posted.



Thanks,



Rob Strecker

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