Abstract: A retrofit module for attachment to an injection molding machine having a plasticizing and injection unit includes a module plasticizing and injection unit, and a support assembly to secure the module plasticizing and injection unit on the injection molding machine independently from the plasticizing and injection unit of the injection molding machine. The module plasticizing and injection unit and the plasticizing and injection unit of the injection molding machine define hereby length axes which extend at an angle of less than 90°. Extending through a nozzle orifice of a platen of the injection molding machine is a nozzle assembly for conducting melt produced by the plasticizing and injection unit of the injection molding machine and the module plasticizing and injection unit. The nozzle assembly is constructed to allow docking of the module plasticizing and injection unit and plasticizing and injection unit of the injection molding machine.

Abstract: The invention relates to a plasticizing unit in injection-moulding machines, in particular for processing thermoplastics, with a plasticizing cylinder in which a rotatable and axially displaceable screw is arranged, at the head of which a non-return valve is provided, which has an axially displaceable barrier sleeve which encloses with radial play a tapered region which belongs to a basic body fixed in the screw head and is present between blades and a stop ring. The basic body has at least three blades, in that supporting elements provided on the surfaces of the blades facing the barrier sleeve, wherein at least the supporting surfaces of the supporting elements are made of a hard-wearing material.