Patent ID: 8900506
Filing Date: 2014-12-02
Classification: B29C

Abstract:
1. A plasticizing screw for injection molding that is installed in an injection molding machine which performs injection molding by plasticizing thermoplastic resin feedstock containing reinforcement fibers, the plasticizing screw for injection molding comprising: a shaft which is rotationally driven; a main flight spirally provided on the circumferential surface of the shaft; and a sub-flight spirally provided on the circumferential surface of the shaft and in a groove portion of the main flight, wherein the protrusion height of the main flight from the circumferential surface of the shaft is formed to be constant in at least an area in which the sub-flight is provided, the sub-flight includes a flat surface portion which is provided on a rear end side in a winding direction and in which a protrusion height from the circumferential surface of the shaft is lower than the protrusion height of the main flight and is constant, and an inclined surface portion which is provided to extend continuously from a leading end in the winding direction of the flat surface portion and in which a protrusion height from the circumferential surface of the shaft gradually increases toward a leading end side in the winding direction and is less than the protrusion height of the main flight, and a connection portion between the flat surface portion and the inclined surface portion of the sub-flight is provided further to the rear end side than a central portion in the winding direction of the sub-flight.