Patent ID: 6190601
Filing Date: 2001-02-20
Classification: B29C

Abstract:
A method for controlling a screw injecting apparatus having a heating cylinder and a screw slidably and rotatably received in the heating cylinder and designed to carry out a plasticizing-metering phase in which a predetermined amount of a molten material is accumulated forwardly of the screw by plasticizing and kneading a raw molding material via the screw and the heating cylinder, a waiting phase in which the screw is held inactive for a period between completion of the metering and subsequent injection of the molten material, and an injecting phase in which the molten material is injected, said method comprising:(a) causing said apparatus to vibrate the molten material at a predetermined low frequency axially of the screw during the plasticizing-metering phase;(b) causing said apparatus to vibrate the molten material at a predetermined low frequency axially of the screw during the waiting phase;wherein said vibrations in the plasticizing-metering phase or said vibrations in the waiting phase are produced by an injection cylinder mechanically connected to said screw; and(c) causing said apparatus to vibrate the molten material at a predetermined low frequency in a direction of flow of the material during the injecting phase, wherein said vibrations in the injecting phase are produced by a needle valve mechanism provided for closing an injecting nozzle of said apparatus.