초록 ▼

An injection moulding apparatus (10) includes similar co-injection modules (12) each provided with common supplies (238-242) and supplied with different polymer materials at intermediate pressure by common plasticisers (14-18). Each module has a co-injection nozzle assembly (70) in wich each nozzle

An injection moulding apparatus (10) includes similar co-injection modules (12) each provided with common supplies (238-242) and supplied with different polymer materials at intermediate pressure by common plasticisers (14-18). Each module has a co-injection nozzle assembly (70) in wich each nozzle (148-154) is supplied with polymer at injection pressure by an injector (208) which receives polymer through a non-return valve (220). The injector is mounted alongside the nozzle on a polymer transfer plate (138-146), and has the position of its piston (212) controlled by a hydraulic actuator (214) under the control of a dedicated micro-processor (164) in accordance with a stored injection control program. Each polymer is injected by an injector (208) directly into the associated nozzle (148-154) 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.

대표청구항 ▼

A multi-cavity, co-injection molding apparatus comprising: (1) a plurality of similar modules, each of which comprises: (a) a polymer injection mold defining an injection molding cavity; (b) a co-injection nozzle incorporating a gate opening in communication with said mold cavity, and a polymer flow

A multi-cavity, co-injection molding apparatus comprising: (1) a plurality of similar modules, each of which comprises: (a) a polymer injection mold defining an injection molding cavity; (b) a co-injection nozzle incorporating a gate opening in communication with said mold cavity, and a polymer flow chamber extending from said gate opening and defined by an annular chamber wall; (c) an elongate gate member slidably supported for longitudinal movement in said nozzle and extending through said polymer flow chamber with uniform circumferential clearance from said chamber wall, said gate member defining at one end thereof a gate valve adapted for entering said gate opening thereby to close said gate opening, and said clearance providing a path for polymer flowing through said flow chamber to said gate opening; (d) a gate actuator connected to said gate member and adapted for alternative activation thereby to move said gate member axially alternatively in a direction to cause said gate valve to enter and thereby close said gate opening, or in an opposite direction to withdraw said gate valve and thereby open said gate opening; (e) at least two polymer flow ducts formed in said nozzle, each said duct having an inlet end and an outlet end, said outlet end defines an annular port opening into said polymer flow chamber at said chamber wall, said ports encircling said gate member and being spaced axially apart; (f) at least two polymer injectors, each having respective injector polymer outlet and inlet ducts and a movable injector ram; (g) respective connecting means connecting the respective injector polymer outlet ducts with the respective inlet ends of said polymer flow ducts of said nozzle; (h) respective non-return valves connected respectively to the respective injector polymer inlet ducts, thereby to prevent the back-flow of polymer from the injectors; (i) first and second polymer inlet pipes connected to the respective non-return valves; (j) respective injector actuators drivingly connected to the respective injector rams and (k) respective injector control means connected to the respective injector actuators and adapted to control the positions of the respective injector rams according to respective predetermined ram position-time cycles; (2) at least two polymer supply manifolds, each having a plurality of outputs and a single input; (3) a first set of polymer distribution pipes connecting the respective outputs of a first one of said polymer supply manifolds with the respective first polymer inlet pipes of the respective modules; (4) a second set of polymer distribution pipes connecting the respective outputs of a second one of said polymer supply manifolds with the respective second polymer inlet pipes of the respective modules; (5) a first polymer plasticizer connected to the input of said first polymer supply manifold and adapted to supply a first hot polymer to said first polymer supply manifold continuously; (6) a second polymer plasticizer connected to the input of said second polymer supply manifold and adapted to supply a second hot polymer to said second polymer supply manifold continuously; and (7) respective heating means for maintaining the respective polymers at their respective working temperatures during their passage from the respective plasticizers to the respective injection molding cavities; whereby in each said module, said first hot polymer is supplied by one said injector to one said port in said co-injection nozzle, and said second hot polymer is supplied by the other said injector to the other port in said co-injection nozzle.