Abstract: Pressure working on each support mechanism or on a clearance adjusting mechanism disposed on opposite end portions of a knife rotor and a plain rotor while a sheet material being cut is measured. The clearance adjusting mechanism is actuated to adjust the contact pressure of the knife based on the measured pressure.

Abstract: In a rotary cutter, a contact pressure profile can be adjusted by judging or detecting a contact pressure profile of a knife in its longitudinal direction and heating or cooling respective portions of the knife or plain rotor according to the judged or detected contact pressure profile.

Abstract: A waste removing apparatus is used in a punching machine for manufacturing a carton and removes a waste region of a sheet inserted between a movable die and a fixed die by cutting the sheet along a punching line formed thereon. Two molded plates are provided on the movable die and the fixed die, respectively so as to sandwich a product region of the sheet therebetween. The molded plates have areas slightly smaller than the area of the product region to reliably separate the waste region of a sheet from the product region thereof, even though the sheet is thin and, as such, flexible.