Plasticizing-and Injection Device

Abstract

The invention relates to a plasticizing and injecting device for a plastics injection molding machine comprising a rotationally driven plasticizing screw (8), which is arranged in an axially fixed manner, and an injection plunger (3), which can be moved forward and backwards inside the plasticizing screw (8) by means of a linear drive (1). The injection plunger (3) comprises, at its front end, a non-return valve (2), and an injection cylinder (7) is provided anteriorly of the plasticizing cylinder (9). The invention is characterized in that the non-return valve (2) can, by means of the injection plunger (3) for carrying out an injection processes, be moved forward and backwards inside the injection cylinder (7) between a rear position at the beginning of the injection process and a front position after completion of the injection process. In addition, a melt chamber (13) is formed between the front end of the plasticizing screw (8) and the non-return valve (2), and the melt chamber, during the injection process and during the holding pressure phase, forms an annular gap (30) between the injection plunger (3) and the injection cylinder (7) for receiving plastic melt as the plasticizing screw (8) continues to rotate during injection.

Dependencies are inferred from the claim text.