INJECTION MOLDING SCREW OF METAL

摘要

PROBLEM TO BE SOLVED: To prevent the occurrence of a stagnant material, and to reduce the rotational resistance and the sliding resistance to a screw by limiting the terminating end position of a screw flight at a predetermined position in relation to the position of a feed port in a heating cylinder. SOLUTION: The screw 16 is provided in the heating cylinder 10 having a nozzle 11 on its tip in a rotational and advancing/retracting manner. Granular metal fed inside from the feed port 13 of a rear portion of the heating cylinder are melted while transferred forward by the rotation of the screw. The measured molten metal is advanced and injected from the nozzle 11 into the tip portion of the heating cylinder 10. The screw flight 19 formed on the outer circumference of a shaft of the screw 16 is provided in a limited manner so that its terminating end 19a is located below a rear edge of the feed port 13 in the retraction limit of the screw in the heating cylinder, and located forward of the feed port 13 in the advancement limit of the screw and the feed port 13 is closed by a rear portion 18a of the shaft 18.