Rolls, sheets and strips are transported into the cutting chamber by means of profiled draw-in rollers. Precut material is fed via a feed chute. Size reduction to the desired end size is performed between the stator- and rotor knives in the housing. The end fineness is determined among others by the speed of the rotor and the type of screen insert. High-speed models with special rotors and screens are used for continuous pulverization of sheet- and roll cellulose.