Injection molding machine and injection molding method

An injection molding machine, comprising:

• a plasticizing unit which plasticizes a molding material inside a plastication cylinder by rotation of a screw;
• an injection unit which injects, into a mold, the molding material supplied into an injection chamber of an injection cylinder from the plasticizing unit;
• and
• an injection control section which controls operations of the plasticizing unit and the injection unit, wherein
• the plasticizing unit comprises a rotary driving device rotating the screw,
• the injection unit comprises a plunger reciprocally moving inside the injection chamber, and an injection driving device reciprocally moving the plunger, and
• the injection control section is configured to driving the injection driving device to move the plunger backward and forward inside the injection chamber and driving the rotary driving device to alternately rotate the screw in a normal clockwise or counter-clockwise rotation direction and a corresponding reverse counter-clockwise or clockwise rotation direction, and controlling the molding material to flow back-and-forth between the inside of the plastication cylinder and the injection chamber, and the injection control section is configured to
• driving the rotary driving device to rotate the screw in the normal clockwise or counter-clockwise rotation direction, extruding the molding material from the inside of the plastication cylinder into the injection chamber, moving the plunger backward, and stopping the plunger in a metering completion position;
• and
• driving the rotary driving device to rotate the screw in the reverse counter-clockwise or clockwise rotation direction, driving the injection driving device to move the plunger forward, and pushing back the molding material from the inside of the injection chamber into the plastication cylinder.