Injection molding machine

摘要

Upstream of the nozzle (7) a cylindrical chamber (5) contains a circular pin piston (4), with a cross sectional area smaller than that of the chamber. A reverse-flow plug (8, 9) separates the plasticizing cylinder (1) from the cylindrical chamber (5). Preferred Features: The plug is formed by the screw tip (9) and a corresponding sealing seat (8). The screw (2) has limited axial movement in the plasticizing cylinder. The piston (4) extends into an axial bore of the screw. The tip of the screw has a special sealing projection. The cylindrical chamber (5) enlarges, upstream of the seat (8). The plasticizing cylinder is connected via a heating channel with other cylindrical chambers. These are mutually axi-parallel, the heating channel running perpendicular to them. A central plug on the heated channel, separates chambers when operated (allows varied pressure injections). The screw has a passage through which the piston forming a plug extends and is sealed. It extends into the heated channel. Screw and/or pin piston with piston rod are connected to a double-acting piston machine. The nozzle opening is arranged in a preferably heated nozzle section, which can be introduced into a mold with a central nozzle tip. Upstream of the nozzle, a sealing unit seals the nozzle section against the mold. The cylindrical chamber and/or the plasticizer cylinder and/or the nozzle section can be heated. A hot channel nozzle follows the cylindrical chamber. The plasticizing cylinder has a device to supply fibrous plastic. The form of the screw near the supply unit, is suited for the cross sectional shape of the fibrous material.