초록 ▼

An injection molding machine [10] for molding plastic parts by injecting a molten plastic through a plurality of valve gates [31] into a mold cavity by reciprocation of a helical screw [16]. A linear position sensor [34] positioned on the machine to detect the position of the helical screw [16] and

An injection molding machine [10] for molding plastic parts by injecting a molten plastic through a plurality of valve gates [31] into a mold cavity by reciprocation of a helical screw [16]. A linear position sensor [34] positioned on the machine to detect the position of the helical screw [16] and control the opening and closing of the gates [31] based on the detected position of the screw [16]. A computer is in communication with the valve gates and the position sensor to monitor the position and activate the opening and closing of the valve gates [31]. A pressure transducer is associated with the mold cavity and in communication with the computer [32] as an alternate or additional method for controlling the opening and closing of the valve gates [31].

대표청구항 ▼

[ What is claimed is:] [1.] A method for injection molding a plastic part, including an injection molding machine, having a barrel filled with a molten material and a reciprocating screw therein, the barrel in fluid communication with a pair of mold halves, the method comprising:closing the pair of

[ What is claimed is:] [1.] A method for injection molding a plastic part, including an injection molding machine, having a barrel filled with a molten material and a reciprocating screw therein, the barrel in fluid communication with a pair of mold halves, the method comprising:closing the pair of mold halves to form at least one mold cavity in the shape of the part or parts to be molded;positioning a plurality of normally closed valve gates across the surface of one of the pair of mold halves;monitoring the position of the reciprocating screw as it moves through a length of travel from a home position to an end position;programming a computer associated with the machine to open and close said plurality of valve gates during a single length of travel of the reciprocating screw, said plurality of valve gates in communication with said computer to each open and close based solely on the position of the screw as it moves through said length of travel;positioning the screw in said home position based on the part or parts to be molded during a given molding cycle; andmoving the reciprocating screw from said home position to begin said given molding cycle, said movement causing said computer to open at least one of said plurality of valve gates based on the linear position of the screw, allowing molten material to flow into said at least one mold cavity through said at least one open valve gates; andcontinuing to move the reciprocating screw toward said end position, said movement causing said computer to close said at least one open valve gate based on the linear position of the screw preventing molten material from flowing therethrough, said continued movement causing said computer to open another of said plurality of valve gates based on the linear positions of the screw allows molten material to flow through said another open valve gate.