Perforator für Metallplatten

摘要

A perforator for presensitized plate has plural punches and a die array cooperating with the punches. A stripper plate retains the plate adjacent the die array when punches separate from the die array after the punches form punched holes in the plate. The punches and/or the die array is coated with non-crystalline hard carbon. The punched holes are formed in the plate. In a preferred embodiment, the coating of the punches and/or die array has a surface whose roughness is 0.8 mu m or less. A clearance defined between the punches and the die array is 10 to 30% of the thickness of the plate. Each advancing end of the punches is provided with a cylindrical tip portion of lesser width than the rest of the punch. The stripper plate is provided with a cushioning material mounted for contact with the plate.