'Lo all,
        Am asking the following for a colleage, so I hope I get
all the right data in. Here goes:
        The facts:
                -we process the HSA flex for an HDD assembly. We are presently in
over our heads with foreign contaminants namely fibers, white
residues, and solder balls on the flex surface and our customer wants
no evidence whatsoever of such contaminants once the flexes reach
them.
                -since manual screen printing is in use, the solder balls issue was
addressed via the regular cleaning of the stencil with lint-free
wipes and  a cleaning agent, Tri-clean, frequency of  cleaning
previously deter. thru evaluatory runs. This procedure significantly
reduced the solder balls, but later proved to be the primary source
of teh fiber contaminants( the wipes).
                -Several other wipe types were evaluated and some proved to address
the fiber issue but made the solder ball spectre reappear. So now
were in quite a dilemma. Loose the fibers, you get sol. balls, vice
versa. By the way, the production line is not a clean-room
nvironment.
                -The idea of shifting to a different cleaning method
came up but so far, nada.

        The question: Is there an alternative cleaning method in use which
removes /reduces solder accumulation under the stencil(no smears-no
solder balls) but does not deposit foreign contaminants(fibers,etc)
on the flexes(say, new wipe material).

        All ideas are very welcome. Sorry, this sure was a long one.

                                                                                Marc



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