Injection molding apparatus and molding method with use of the apparatus

Abstract

An apparatus comprising a resin plasticizing injection machine having an injection nozzle, a branch portion connected to the injection nozzle and having a plurality of outlet ports, molds and mold clamping devices both arranged around the branch portion in corresponding relation to the outlet ports, and an extension nozzle for maintaining each of the outlet ports in communication with each of the molds. Pressure control means is provided at an intermediate portion of the extension nozzle for maintaining the mold cavity at a specified pressure after resin has been injected into the mold. Means is provided for closing a flow channel extending from the injection machine to the pressure control means. After resin has been injected into a mold, the cavity of the mold can be maintained at the specified pressure by the pressure control means in place of the injection machine, so that the injection machine and the next mold can be subsequently brought into operation. Preferably resin is injected into one mold after another in succession in such a manner that the first mold is prepared for the injection of resin again before the injection machine is made ready for the injection into the first mold after completing the injection of resin into all the molds. The flow channel closing means comprises a shutoff valve mounted on each of the extension nozzles. The branch portion may comprise a branch valve for selectively opening or closing the flow channel.

Dependencies are inferred from the claim text.