OPERATIONAL METHOD OF TWO-STAGE INJECTION MOLDING MACHINE, PLASTICIZATION OF MATERIAL IN TWO-STAGE INJECTION MOLDING MACHINE, AND METHOD AND SYSTEM FOR TRANSFERRING MELT

摘要

PROBLEM TO BE SOLVED: To minimize a shear force to a melt so as to decrease a polymer decompressed product by providing an injection pot capacity substantially equal to the volume of the melt accommodated therein when a molten material is plasticized. SOLUTION: A granular plastic material 51 entering from a hopper 56 into a barrel 54 is transferred to a barrel head portion 61 at the front end portion of the barrel 54 by rotating a screw 50, which is then transferred to an injection pot 63. The rotational and the axial movements of the plasticization screw are then adjusted to the axial direction of an injection plunger 64 such that the rotational and axial speeds of the screw 50 are carefully controlled and the capacitance of the injection pot 63 is substantially equal to the volume of the melt accommodated therein. This permits the amount of the molten material to be transferred through a distribution valve 62 to the injection pot 63. Thus, since the injection plunger 64 is controlled such that the injection plunger 64 is returned by an injection piston, the amount of the shear force applied to the melt can be decreased.