Die set with disposable molybdenum die plate and improved window plate for universal gang-punch tool

Abstract

A die and method of gang punching selective holes in thin sheet materials such as greensheets are provided in which slugs of greensheet material formed during the punching operation easily fall through the die and are removed. The die uses a number of plates one of which is a window plate having openings corresponding to openings in a die plate disposed thereon. The window plate openings have a larger diameter than the die plate openings and also a plurality have an oval shape which oval shape openings provide less resistance to the falling slugs and facilitate removal of the slugs from the die. The window plate also preferably has a central grid open area with the remainder of the plate having vertical through-holes corresponding to the through-holes of the die plate. The die also preferably employs a die plate made from at least two sheets of material, i.e., an upper disposable sheet (die plate) and a lower sheet (sub-die plate) wherein the upper die plate is made from a wear-resistant material such as molybdenum. The upper die plate is preferably made by photolithography techniques.