METHOD AND APPARATUS FOR CONTROLLING INJECTION OF INJECTION MOLDING MACHINE

摘要

PROBLEM TO BE SOLVED: To provide a method and an apparatus for controlling injection of an injection molding machine capable of obtaining stable moldings with a small dispersion of weight and accurately discriminating a defective with a small dispersion of residue. SOLUTION: The method for controlling the injection of the injection molding machine comprises the steps of positional feeding back by an injection servo motor 8 and an encoder 9 after finishing a first sucking-back step of moving a screw 3 until the screw 3 arrives at a first sucking-back position completing position, and holding the screw 3 at the first sucking-back completing position. The method further comprises the steps of pressure feed-back controlling by a rotary servo motor 4 and a load cell 7 for a predetermined time after the first sucking-back step while the position of the screw 3 is holding, rotating the screw 3 in a forward direction of a rotating direction for clamping a backflow preventing mechanism 2 against the screw 3, and maintaining a molten resin density in a heating cylinder constant.