TANDEM TYPE INJECTION MOLDING MACHINE

PURPOSE:To make it possible to prevent the leakage, stagnation and deterioration of a resin between a cylinder and an injection plunger, by mounting a first screw imparting rotary action as main action and performing the plasticization of a resin and a second screw performing an injection process accompanying movement in the axial direction as main action and bringing about rotary action as a side effect. CONSTITUTION:The resin 2 supplied to a hopper 1 is plasticized by the rotation of a first screw 3 at an almost constant position and passes through the supply port 12 of an injection cylinder 7 to be weighed in front of the injection cylinder 7 by a second screw 6 rotating at a relatively low speed by a motor 8. At this time, a small amount of the resin 10 supplied to a second hopper 11 is also transported in front of the injection cylinder 7 in a plasticized state by rotating the second screw 6 and met with the resin 2 to be weighed. When the second screw 6 is allowed to advance by a hydraulic cylinder 9, a check valve 5 is operated by the pressure differ ence between the resins to be closed and the rearward leakage of the resin is prevented and the resin is injected to a mold through a nozzle 4. Because cleaning can be performed by the solid phase resin 10, the resin 2 is prevented from leaking to the rear side of the injection cylinder 7 and resin replacement and color replacement properties are enhanced.