Your welcome, it is called Piercing.
Piercing this is the art of cutting away areas of an object for a useful (as in sifters, casters etc) or for pure decoration. The early form of piercing was achieved with chisels and punches, since around 1765 it has been done with a piercing saw or in the case of mass production, dies and fly presses. See piercing: http://www.925-1000.com/silverglossary4.html
In my opinion in some cases, pending on size and shape of the silver item/sheet, perhaps a silver factory with specialized personnel could have operated a pedal driven piercing saw but I have never seen one.