Mr. Brunker,

I done on/off studies of various plastic materials for the
application of squeegee blade for solder paste printing.  One
purpose of my study was to eliminate stencil wear that  you
mentioned using a metal blade such as a Transition Automation
Permalex metal squeegee, and at the same time to eliminate
the printing problem associated with using a polyurethane
rubber squeegee.

By using these materials, I had good success reducing stencil
wear significantly, and bringing printing quality to that of metal
squeegee.  Is this something you are looking for?  One major
factor of stencil wear  is due to uneven support of boards during
printing cycles.  Board-Lok support jigs from Transition
Automation provide even support and eliminate many printing
defects associated with double sided printing.

Regards
Matthew Park
Norsat International Inc.


>>> Edward Brunker <[log in to unmask]> March 18,
1999  2:38 am >>>
     Hi,
     Has anyone done any studies for the change of depth of
solder paste
     with wear on the stencil. Metal blade squeegees damage the
stencil
     over a period of time, yielding an uneven surface in the form of
     furrows in the direction of travel. Any uneveness in the stencil
is
     going to hold the blades that much further off the board giving
more
     solder paste.
     Any comments?
     Regards
     Edward Brunker

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