PLASTIC NUCLEAR AND MIXING DEVICE FOR DIRECT PROCESSING AND ADMINISTRATION OF PLASTIC REGENERATIVE MIXTURES AND PLASTIC PRIMARY MATERIALS ON INJECTION MOLDING MACHINES

摘要

The invention relates to a plasticising screw and a mixing device for plastics processing with the plasticising unit being of normal length, having a feed zone, a compression zone and a metering zone, the mixing device comprising a shearing element and a mixing part being arranged in the metering zone. According to the invention, the metering zone is shortened by at least 2D. Arranged in this region before the screw tip is the mixing device, which comprises a plurality of shearing rings and mixing parts which alternate and can be interchanged with one another as desired. Each mixing part is made up of two mixing discs, which have axially directed clearances distributed around the circumference. Between the clearances there are webs, which are inclined in the axial direction. The mixing discs are arranged in pairs axially with respect to each other in such a way that at the circumference they form a triangular annular channel with respect to the plasticising cylinder. Radially, they are offset in such a way that a clearance lies opposite each web. The core diameters of the mixing discs and of the shearing rings correspond to the core diameter of the plasticising screw in the metering zone and the outside diameter of the mixing discs corresponds to the nominal diameter of the plasticising screw. The design and arrangement of shearing rings and mixing parts ensures for the first time the direct processing and colouring of mixtures of reclaimed plastic and of primary plastics materials on injection-moulding machines with the plasticising unit being of normal length.