On Wed, May 18, 2011 at 10:15 PM, Jesse Lackey
<jsl-ml@celestialaudio.com> wrote:
> Hi - I get this sometimes too, it seems to happen more often when the
> 'print' thru the stencil isn't sharp, i.e. the little rectangles of
> solder paste are 'blurry'. =A0My guess is that some of the paste is off
> the pad, and doesn't necessarily automagically recombine with the paste
> that is on the pad. =A0So, because of the solder mask, it kind of balls u=
p.
>
> Spraying with flux remover and scrub with toothbrush helps, but does not
> solve it.
>
> The cleaner the 'print' (I use a prototype grade metal stencil) the
> better the results. =A0There is something to the angle of the squeegie
> blade, the speed moving it, how much paste on the stencil your smearing,
> downward force, alignment of stencil, ... all have an effect on results.

Hmm...interesting. I think I'll try to reduce the size of the
apertures on my next stencil. That will hopefully mean the process
will be a bit more tolerant of the small misalignment I'm inducing to
the stencil.

Thanks!

Josh
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