PLASTICIZING SCREW FOR INJECTION MOLDING AND INJECTION MOLDING METHOD USING SAME

摘要

This plasticizing screw for injection molding is provided with a shaft, a main flight, and a sub-flight, and is installed in an injection molding machine that performs injection molding by plasticizing a thermoplastic resin starting material containing reinforcing fibers. The protrusion height of the main flight from the shaft peripheral surface is formed in a fixed manner at least at the region at which the sub-flight is provided. The sub-flight is provided with: a flat-surface section that is provided to the back-end side in the direction of winding and that has a protrusion height from the shaft peripheral surface that is fixed and lower than that of the main flight; and a tilted-surface section that is provided in a manner so as to extend continuously from the front end in the direction of winding of the flat-surface section, and that has a protrusion height from the shaft peripheral surface that gradually increases in the direction towards the front-end side in the direction of winding within a range that is lower than the main flight.