A method for making perforations in a continuous film which is thereafter cut into individual filmstrips having variable lengths. A die set unit of the perforator has a plurality of punches and corresponding dies which are respectively arranged along the continuous film. The die set unit performs die-punching...http://www.google.de/patents/US5697272?utm_source=gb-gplus-sharePatent US5697272 - Method of perforating film
