INJECTION MOLDING MACHINE WITH AUXILIARY PACKING MEANS

摘要

An injection molding machine or system in which an auxiliary packing stage is provided between a plasticating stage and a molding stage. The packing stage comprises a tubular housing and a ram member disposed for sliding displacement therein by a drive unit. The ram member is reciprocated in the tubular housing to intermittently develop a packing chamber therein to allow an amount of the extruded material from the plasticating stage to be accepted temporarily in the chamber and to intermittently reduce the volume of the chamber to discharge the accepted amount of the melt under pressure into a mold cavity in the molding stage. A control unit acting on the drive unit establishes a predetermined stroke and rate of each displacement or reciprocation of the ram member in conjunction with the volume of the mold cavity and the kind of the material to be molded. The extruded amount of the material is adjusted in conjunction with the volume of the mold cavity.