The machine is a type of twin-roll mill that has been designed specifically for recycling waste from production of technical parts, as well as waste arising from retreading truck tyres. It accepts material that has been pre-cut to a particle size of 4 mm or less, and which is fed to it continuously by a series of screws positioned along the gap between the rollers.The Karakal relies on friction to reduce the size of the rubber particles. The particle size is reduced by shear, not by cutting, and this produces powder with rough surfaces. The size of the powder particles can be accurately controlled, says the company.The machine has two main rollers with a diameter of 400 mm and a length of 1,000 mm, each covered with micro-serrations. Roller speed and direction of rotation are controlled via variable-frequency drives. The distance between the rollers can be adjusted to an accuracy of 0.1 mm. The rollers are pretensioned by an assembly of springs and a hydraulic cylinder.The temperature at which the process runs is also controllable. Process air is used to cool the powder. The rolls are segmented, and the surfaces sections can be taken off, so that the serrations can be resharpened by the user. Two additional smaller rollers located below each of the two main rollers to clean them can be fitted on request.