Method of continuous injection molding of plastic articles

Abstract

A method of injection molding plastic articles using a rotor assembly that continuously rotates past a stationary extruder that supplies molten plastic material to the assembly. The rotor assembly includes a plurality of mold assemblies, each mold assembly having a pair of separable mating die members which are selectively opened and closed. A plurality of injection chambers is disposed within the rotor assembly in cooperating relationship with each pair of die members. The rotor assembly is continuously rotated past the extruder and molten plastic material is supplied directly into the bottom of each injection chamber. The rotor assembly is then rotated to a position where a ram is driven into the injection chamber to force material in the chamber into a mold cavity formed by the mold assemblies. During rotation of the rotor assembly from the extruder to the ram, the molten material is retained in the injection chamber by adhesion between the material and the walls of the injection chamber. Each mold assembly is opened after the plastic material therein has solidified, the solidified material is removed, and the mold assembly is again closed before it reaches the extruder.