Pre-plasticizing type injection molding machine and control method therefor

Abstract

A pre-plasticizing type injection molding machine includes a plasticizing device for plasticizing a molding material supplied from a hopper by a first screw disposed within a first barrel, an injection device 8 for measuring a molten resin supplied from the plasticizing device 5 and for injecting the measured molten resin by a second screw disposed within a second barrel. A switching valve is provided in a resin passage between a resin outlet of the plasticizing device and a resin inlet of the injection device, and an accumulation device is provided for housing a pushing plunger having a stock chamber communicated with the resin passage at a position between the switching valve 10 and the resin outlet of the plasticizing device. The injection molding machine further includes a control portion for driving the first screw for continuous rotation during the molding step, closing the switching valve and shifting the second screw forward during an injection step, and opening the switching valve, driving the second screw for rotation and driving the pushing plunger forward during a measuring step. Thus, by continuous operation of the plasticizing device, the performance of the plasticizing device can be maximized. In conjunction therewith, the degree of mixing and uniformity of a composite resin can be enhanced.

Dependencies are inferred from the claim text.