What stencil design guidelines differ when one decides to go with

a -400/+500 particle size solder paste? The paste companies tout that the

finer particle paste offers print improvements below 20 mil pitch. But I

believe one would have to reduce the aperture sizes all around because more

metal would be deposited in each one. Is this accurate? How much reduction

is needed. Is home-plating the apertures even more important? I could not

find this topic in the archives. We are considering switching for our

finer-pitch boards, as their pitch decreases, if it really offers an

advantage. However, we have been printing 20-mil for a long time

with -325/+500 paste for quite a while.

-Ryan Jennens

TelGen Corporation