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United States Patent 5028226
Douris , ê et al. July 2, 1991

Multi-cavity, co-injection molding apparatus

De'ath , Ê et al. July 2, 1991

Abstract

An injection moulding apparatus includes similar co-injection modules each provided with common supplies and supplied with different polymer materials at intermediate pressure by common plasticisers. Each module has a co-injection nozzle assembly in wich each nozzle is supplied with polymer at injection pressure by an injector which receives polymer through a non-return valve. The injector is mounted alongside the nozzle on a polymer transfer plate, and has the position of its piston controlled by a hydraulic actuator under the control of a dedicated micro-processor in accordance with a stored injection control program. Each polymer is injected by an injector directly into the associated nozzle and is controlled solely by injector operation, and without the use of any control valve between the injector and the nozzle. The module micro-processors are controlled by a host processor which organizes the operations of the apparatus.