> >> In the past, one could get chemically etched stencils, but they didThe chemical etching was difficult to control to keep the sidewalls of the
> >> 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"?
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.htm
Thanks
Ron