| 摘要 |
PROBLEM TO BE SOLVED: To provide a preplasticating injection molding apparatus which prevents the corrosion of metal due to pitting corrosion in the upper part of the front wall of the injection cylinder chamber, in cases involving high-speed injection molding of a resin material plasticized at a low viscosity and suck back. SOLUTION: In the preplasticating injection molding apparatus, a resin material plasticized in a plasticization cylinder is fed to an injection cylinder chamber within an injection cylinder through a connection passage connecting the plasticization cylinder with the injection cylinder and injected from an injection hole of an injection nozzle with a plunger, while the plasticized resin material is caused to flow out into the injection hole through a by-pass passage opened at a position nearly symmetrical to the injection hole in the connection passage opened to the peripheral edge of the front wall of the injection cylinder chamber. An auxiliary by-pass passage communicating with the injection hole is opened at a position close to the part where the corrosion is to occur, or close to the opening of the connection passage, and nearly symmetrical in the connection passage. COPYRIGHT: (C)2010,JPO&INPIT |
