Mr. Windsor:
Post your fax number, so I may fax you a solderpaste
aperture shape that I use for the complete elimination of
solderballs for chip components.  It was proven it works
better than home plate shape.

regards
Matthew Park

>>> Clinton Windsor
<[log in to unmask]> January
7, 1998  1:27 am >>>
Dear Technetters,

We are trying to eliminate the occurence of solder balls in
our
production line by trialling various aperture shapes and
reductions on
the screen printer stencil.  The nature of the solder balls
suggests
that paste is being trapped under the component and then
forms a solder
ball which adheres to the side of the component.  I have seen
this type
of solder ball referred to as a "squeeze ball".  We have tried
the so
called "home plate" (trapezoidal) shaped apertures with
considerable
success on nearly all the components except for the 0603
capacitors.

I would be interested to hear any ideas or suggestions of
other aperture
shapes or designs which could help solve this problem.

Thanks in advance,
Clinton Windsor

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