> >> In the past, one could get chemically etched stencils, but they did
> >> not work anywhere near as well as the laser cut ones.
> >
> > What were the problems with the chemically etched compared to laser
> > cut? IOW, please explain "work anywhere near as well"?
The chemical etching was difficult to control to keep the sidewalls of the
etched area flat and uniform. The variability of the process was a real
problem.
We might have one stencil that was perfect, others would create multiple
problems with paste release. There were also headaches with the etch being
non-uniform, thus one often times had to tweak the paste mask and change
sizes depending on pad size and aspect ratio.
Here is a link to a fellow that gives an overview of both processes.
http://www.smt.com/p8.htmThanks
Ron