Abstract: A method of manufacturing a catalyst, a catalyst precursor, or a catalyst support comprising: (a) mixing a refractory metal oxide or precursor thereof with a liquid to form a paste; (b) adding said paste to an extruder, the extruder having a die plate comprising one or more dies, each die having a plurality of apertures, the outlet of each aperture having a cross sectional area of 6 mm2 or less; (c) extruding the paste through the apertures to form catalyst support extrudates; wherein the inlet of the apertures has a greater cross sectional area than the outlet of said apertures; and wherein for at least one die the combined cross sectional area of all apertures at the inlet relative to the total cross sectional area of the die at the inlet is higher than 50%.

Abstract: A method and apparatus for forming an article from mouldable material is disclosed. A mouldable material, such as a thermoplastic is heated until it is molten and is fed into an injector (900) of an injection moulding apparatus. A liquid, such as water, is introduced (930) into the stream of molten plastic. Because the molten plastic is at a temperature above the boiling point of the water, the water will boil and will expand the plastic material forming a honeycomb structure of bubbles that remains once the material has cooled.

Abstract: An apparatus for highly controlled color composition and distribution within the face mix of semi-dry concrete mix paving stones is disclosed.

Abstract: In a feed block, a main conduit and sub conduits are formed. High-viscosity dope flows through the main conduit, and low-viscosity dope flows through the sub conduits. Distribution pins are disposed in a joint portion where the sub conduits intersect with the main conduit for controlling the flow volume of the low-viscosity dope. A tapered cutout is formed in the peripheral surface of the distribution pin. The distribution pin is attached in such an orientation that a wider side of the cutout coincides with the lower reaches of a dope flow. Since ledges are formed in both ends of the cutout, the amount of the low-viscosity dope flowing through the cutout is smaller in both widthwise ends than in the middle.

Abstract: Apparatus and method whereby coinjection molding shooting pot actuation structure is configured to be installed in a coinjection hot runner with a coinjection nozzle, the coinjection nozzle having at least two melt channels ending at the same gate. The shooting pot is preferably disposed in one of a mold cavity half and a mold core half. A shooting pot piston is configured to discharge a melt from the shooting pot. A transmission structure is configured to (i) extend through one of the mold cavity half and the mold core half, and (ii) to transmit a force to the shooting pot piston. Actuation structure is disposed on the opposite side of the mold cavity half from the coinjection hot runner, and is configured to provide the force to the transmission structure. This configuration conserves space in the mold.

Abstract: A superabrasive grain setting apparatus is provided for arranging superabrasive grains on a surface of a manufacturing mold used in manufacturing a grinding tool. The apparatus comprises a grip and raising mechanism for gripping the mold in a horizontal state and for turning the mold to a vertical state; a six-axis control robot composed of a base arm mechanism with three controlled axes and a wrist unit with three controlled axes attached to the base arm mechanism; a superabrasive grain supply device having a grain storage for storing the superabrasive grains and a grain separation mechanism for separating the superabrasive grains in the grain storage one by one to a suction position; and a suction nozzle detachably mounted on an endmost arm of the robot and provided with a bent nose portion for drawing a grain of superabrasive to a nozzle end thereof at the suction position.

Abstract: A coinjection molding apparatus includes a manifold, a nozzle body coupled to the manifold, a sleeve disposed within the nozzle body and defining an outer melt channel between the sleeve and the nozzle body, a pin disposed within the sleeve and defining an inner melt channel between the pin and the sleeve, and a nozzle tip having an alignment portion contacting the sleeve. The sleeve is actuated to open and close melt communication of the outer melt channel and a cavity gate. The pin is actuated to open and close melt communication of the inner melt channel and an opening of the sleeve. The alignment portion aligns the sleeve with the cavity gate along the actuated range of the sleeve.

Abstract: An apparatus for introducing a pressurized gas includes a pressurized-gas supply-source, a plurality of measuring tanks, a first pressurized-gas supply-line, pressurized-gas supply valves in the first pressurized-gas supply-line, second pressurized-gas supply-lines and pressurized-gas discharge-control valves disposed in the second pressurized-gas supply-lines. A combination of the measuring tanks is determined on the basis of the amount of a pressurized gas required for forming a hollow portion in a molded article, and the pressurized-gas discharge-control valves disposed in the second pressurized-gas supply-lines are controlled on the basis of the above determination.

Abstract: A method of feeding a composite molten resin capable of easily forming a multi-kind-multi-layer preform. An apparatus for feeding the composite molten resin has a nozzle portion which includes an outer discharge port in which an outermost annular flow path through which a main layer-forming molten resin flows, meets an outer annular flow path through which a sub-layer-forming molten resin flows inside of the outermost annular flow path; and an inner discharge port in which a shell layer-forming molten resin annularly flowing inside of the outer conflux path, meets the core layer-forming molten resin flowing inside the shell layer; the outer discharge port and the inner discharge port being arranged in this order from the downstream toward the upstream in a direction in which the molten resins flow; wherein provision is made of a shaft-like opening/closing valve for opening and closing the inner discharge port, and a gear pump for intermittently discharging the sub-layer-forming molten resin.

Abstract: In a method and apparatus for making an article with a microstructure or nanostructure, an injection molding process or an injection-compression molding process is used to produce a substrate and to apply a microstructure or nanostructure upon a surface of the substrate. Subsequently, the substrate is inundated with a cross-linking, curing material.

Abstract: The present invention discloses a multi-gate assembly for creating a composite article, typically including a mold including a closed interior cavity, a first mixing gate in communication with the mold, and at least one iso-based polymer material and at least one poly-based polymer material concurrently fed into the first mixing gate. At least one filler material is fed into a second gate in communication with the first gate, and a composite associated with the iso/poly/filler materials is communicated into the cavity for formation into a three-dimensional article.

Abstract: Coinjection molding system control apparatus and method preferably includes flow control structure and/or steps configured to reduce pressure on a second melt, preferably causing a relatively small portion of a first melt to flow from a distal portion of a first melt channel in the coinjection nozzle into a distal end of a second melt channel in the coinjection nozzle. This prevents substantial amounts of the second melt from being dragged into the mold cavity when the next shot of the first melt is injected.

Abstract: There is provided a flat die adapted to achieve a desired thickness distribution without a complicated structure even in laminating resins having different viscosities in molding. A flat die 1 of the present invention includes a resin inlet portion 20, a manifold 21 connected to the resin inlet portion 20, and a lip opening 12. The flat die 1 further includes a projecting cavity 22, whereby, when resins of different kinds flow in the manifold 21 in a laminated condition in a thickness direction, each of the resins spreads in a different way in the width direction.

Abstract: Inventive machine allowing the simultaneous fabrication of several objects by a method of “rapid prototyping” type, by depositing a succession of layers of heat-fusible fluid. It chiefly comprises a crossbar (20) carrying two platforms (11) on each of which an object is fabricated by deposition. Two fixed work stations are arranged diametrically opposite each other so that the jet (12) of each of these fixed stations can perform a depositing operation at the same time as the other jet (12). After each deposit, the crossbar is rotated 180° to alternate the depositing operations of the two different materials. Particular application to prototyping jewellery models.

Abstract: Center filled confections, such as gummy or jelly candies or fruit snacks are continuously produced by co-deposition into a mold without candy tailing to obtain products with substantially uniform side walls and little, if any, shell breakage and filler leakage or bleed-out problems. Decentering of the filler and its accompanying production of thin or weak shell walls is avoided by at least substantially preventing excessive flow of a fluid or liquid shell component along a single side of shell introduction into the manifold nozzle or nozzle cavity. At least substantially uniform flow of the shell component in an annular passageway of a co-deposition nozzle assembly may be achieved with an apertured disk insert, a plurality of manifold bores, or opposing shell component entry points to evenly distribute the shell component and prevent or substantially reduce filler leakage or bleed-out.

Abstract: A method for manufacturing a multi-resin composite article is provided. The method comprises providing at least one fiber preform in a mold; injecting a plurality of resins into the at least one fiber preform at a plurality of locations on the at least one fiber preform; and forming at least one transition region along a mutual contact surface between the resins. Each of the at least one transition regions is defined by a gradual transition in composition from one of the resins to another of the resins. A multi-resin composite article is also provided. The article comprises: at least one fiber preform; a plurality of resins, wherein the at least one fiber preform is infused with the resins; and at least one transition region extending along a mutual contact surface between respective ones of the resins. A system for manufacturing such a multi-resin composite article is also provided.

Abstract: Described herein is injection-compression moulding of articles made of plastic material with two components by means of a press of the stack-mould type, in which the first and second countermoulds are constrained to the corresponding moulds carried by the rotating central element of the press so as to enable the respective cavities to set themselves in a position of partial opening for the injection of the plastic material within them. To both of the cavities there is then applied a closing force to bring about compression of the plastic material injected therein.

Abstract: Injection molding machine apparatus and method with moving platen injection and ejection actuation is provided for an injection molding machine clamp assembly configured to clamp a relatively movable platen to a relatively stationary platen. Injector structure is coupled to the relatively movable platen and is configured to actuate a molten material injection structure when the relatively movable platen and the relatively stationary platen are closed. Ejector structure is coupled to the relatively movable platen and is configured to actuate a molded article ejection structure when the relatively movable platen and the relatively stationary platen are open.

Abstract: A gate adapter for use in a hot runner co-injection molding system includes a hollow gate adapter body defining a gate outlet at a free end thereof. At least a pair of nozzle assemblies is disposed in the adapter body, each of nozzle assemblies having an inlet end in fluid communication with a source of liquid extruded material and an outlet end in the adapter body. At least a pair of nozzle passages is formed in the adapter body and extends from the outlet of the nozzle assemblies to a passage outlet adjacent the gate outlet. A valve stem is disposed adjacent each of the passage outlets and is operable to selectively allow flow from the passage outlets to the gate outlet. The nozzle passages extend for a short predetermined distance within the adapter body to minimize heat transfer.

Abstract: A method in connection with a wind turbine installation for damping tower vibrations, in particular a floating wind turbine installation comprising a floating cell, a tower arranged over the floating cell, a generator mounted on the tower that is rotatable in relation to the wind direction and fitted with a wind turbine, and an anchor line arrangement connected to anchors or foundations on the sea bed. The tower's eigenvibrations, ?eig, are damped by, in addition to control with the controller in the constant power or RPM range of the wind turbine, an increment, ??, being added to the blade angle of the turbine blades on the basis of the tower velocities, ?Z, so that the eigenvibrations are counteracted.

Abstract: A three-dimensional printer uses inkjet-type printheads to rapidly prototype, or print, a three-dimensional model. A powder feeder includes a conveyor system and a metering system to deliver powder to a build area in measured quantities. The powder feeder also includes a vacuum system for loading powder into a feed reservoir or chamber. The vacuum system can also be used to cleanup excess powder. Other powder control features include powder gutters and magnetic powder plows. During printing, a cleaning system operates to remove powder from the printheads. In the event of a printhead or jet failure, the failure can be detected and corrective measures taken automatically. After printing, the model can be depowdered and infiltrated in an enclosure.

Abstract: Mold tooling formed of suitable iron-nickel alloys and provided with a hard electroless nickel coating on the mold cavity surface are useful for high volume production of carbon fiber reinforced, polymer matrix, composites. The iron and nickel alloy provides thermal expansion properties for the molding of dimensionally accurate parts. The nickel alloy coating provides a durable surface, without adversely affecting the expansion properties of the mold, and remains adherent to the base metal during the repeated thermal cycling encountered in high volume production of substantially identical molded carbon composite parts.

Abstract: A fluid injection and exhaust needle for use in gas injection moulding comprising a needle with two separate flow channels; a fluid inlet channel and a fluid outlet channel; wherein gas is injected into the melt via the fluid inlet channel to form a gas cavity in the melt, and gas is simultaneously exhausted from the cavity via the fluid outlet channel.

Abstract: Preform for producing containers (90) comprising a neck section (8), a wall section (6) and a bottom section (7), which is composed of a multi-layer structure comprising three layers, the one of which (1) is directed inwardly respective the preform and is composed of a primary material (PM) thereby forming a primary basis layer (1). Said primary material consists of a synthetic material. A further layer (3) is directed outwardly with respect to said primary layer (1), in such a way that it forms the outer surface layer (3) of the preform, thereby consisting of a tertiary material (TM) forming a tertiary surface layer (3). Said tertiary layer is composed of a further synthetic material. Said preform is remarkable in that an intermediate layer (2) is provided between the primary and tertiary layers (1, 3) which is composed of a secondary material (SM) consisting of a fluid. Process and device for manufacturing said preform.

Abstract: Disclosed herein are methods and systems for forming a plurality of multiple layer plastic articles. The methods and systems utilize shooting pot technology in combination with a combination of thermal control elements and in some instances, specialized flow bore geometries to control a thermal property and a flow parameter of selected polymeric material flowing through the system to mold the plurality of multiple layer plastic articles. Both the systems and methods are well suited for use to perform simultaneous flow injection or sequential flow injection to form the plurality of multiple layer plastic articles. The systems and methods described therein beneficially reduce the mold cavity pitch size for multiple layer molds used with systems having shooting pot technology to a mold cavity pitch size found on conventional monolayer molds to provide a plurality of multiple layer plastic articles having a cost similar to monolayer plastic articles.

Abstract: A co injection manifold assembly for injecting two different materials into a common mold cavity includes a housing that defines a first passage, a second passage and an outlet. The first and second passages communicate with a bore having a valve member for controlling flow of the material through the outlet. A first temperature control element in thermal contact with the first passage and a second temperature control element are in thermal contact with the second passage. Each of the first and second temperature control elements are separately controllable to provide separate temperatures for each of the first and second passages. Separate temperatures in each of the first and second passages provide for the use of materials having dissimilar molten temperatures.

Abstract: This invention relates to methods and systems for forming composite extrudates including at least a base polymer, a plurality of fibers dispersed in the base polymer, and one or more colorants forming a visible, multi-color pattern, e.g., mimicking the appearance of natural wood.

Abstract: A coinjection molding apparatus includes a manifold, a nozzle body coupled to the manifold, a sleeve disposed within the nozzle body and defining an outer melt channel between the sleeve and the nozzle body, a pin disposed within the sleeve and defining an inner melt channel between the pin and the sleeve, and a nozzle tip having an alignment portion contacting the sleeve. The sleeve is actuated to open and close melt communication of the outer melt channel and a cavity gate. The pin is actuated to open and close melt communication of the inner melt channel and an opening of the sleeve. The alignment portion aligns the sleeve with the cavity gate along the actuated range of the sleeve.

Abstract: For easy sanitary maintenance, stable topping of ingredients on rice, and formation of a roll in good appearance, a manufacturing apparatus of rolled sushi is provided with a roll forming sheet (S) fitted to a drive roller (12) and a back tension roller (13) rotating in forward and backward directions so as to be capable of transferring, conveying and winding the rice seasoned with vinegar (P) expanded on the roll forming sheet (S) by rotation of the rollers (12, 13), fitting grooves (20) provided at outer peripheries of the drive roller (12) and the back tension roller (13), fitting shafts (21) provided at end portions of the roll forming sheet (S) for detachably and slidingly inserting into the fitting grooves (20), and a pair of opening and closing rollers (14, 15) provided in an intermediate portion between the drive roller (12) and the back tension roller (13).

Abstract: Apparatus and method for checking the venting of a mold having one or more vents, the apparatus comprising a vacuum source, a flow connection between the source and the mold, and a vacuum gauge connected to the flow connection, whereby vacuum measurement by the gauge correlates with total effective venting area of the mold.

Abstract: Disclosed is: (i) a method of a compounding molding system, (ii) a compounding extruder of a compounding molding system, (iii) a compounding molding system, (iv) a controller of a compounding molding system, (v) an article of manufacture of a controller of a compounding molding system, (vi) a network-transmittable signal of a controller of a compounding molding system, (vii) a compounded molded article compounded by a compounding molding system, (viii) a molten molding material compounded by a compounding molding system, (ix) a component of a compounding molding system and (x) a mold of a compounding molding system.

Abstract: The present invention provides a tool for the production of fiber composite components. The tool has a surface for depositing semifinished fiber products on the surface, the surface having a number of openings for feeding a matrix to the deposited semifinished fiber products. It is consequently possible to dispense entirely or partly with a conventional flow promoter and possible to achieve a high quality of fiber composite component.

Abstract: An injection molding system for injection molding a plurality of molten materials into a mold cavity includes a nozzle, a drop tip supported by the nozzle, and a central bore extending through the nozzle and drop tip. The injection molding system also includes a first and second flow passage each extending through the nozzle, so as to define a first and second nozzle flow passage, and drop tip, so as to define a first and second drop tip flow passage. The first and second drop tip flow passages each include a plurality of branching portions each defining a junction at which the respective flow passage communicates fluidly with the central bore.

Abstract: A method and system for forming an injection molded plastic part. After the injection of plastic material has started, a volume of gas from a fixed volume reservoir is introduced into the plastic material at a low pressure forming a hollow cavity. The gas is introduced into the mold by a gas pin having a temperature sensing device, such as a thermocouple, positioned on it. The introduction of this volume of gas is initiated when the temperature of the plastic material in the mold has reached a predetermined value. After the mold is filled and packed with plastic, pressurized gas is introduced into the hollow cavity forming the completed plastic part.

Abstract: A method and apparatus for combining raw fibrous and binding materials in a single mixing step (Step S3), followed by consolidation (Step S5) so as to greatly shorten the overall cycle time to a finished fiber-reinforced composite part. Chopped fibrous materials and binder materials are deposited sequentially onto a belt conveyor (Step S2) so that the materials are successively layered, one on top of each other in a predetermined ratio, and subsequently mixed (Step S3) to achieve uniform dispersion throughout. The mixed materials are then deposited into a rotating mold (Step S4) to further ensure uniform dispersion of fibrous and binder materials. Impregnation of the fibrous materials with the binder material occur in-situ as the uniformly mixed materials are heated and subsequently compacted in the mold (Step S5) to obtain the desired shape of the fiber-reinforced composite part.

Abstract: An in-mold coat-forming mold and an in-mold coat-forming method are provided, wherein the mold prevents leakage of a coating material for the long term, which is likely to occur when the in-mold coat-forming method is carried out. By disposing a grove, a pressure piece, or both of them so as to serve as coating-material leakage-preventing means, in the vicinity of the edge of a mold cavity adjacent to a shear-structured engaging portion disposed along the circumference of the mold cavity, a coating material is prevented from leaking out of the mold from the engaging portion, and problems such as an adverse affect on a formed product caused by the leaked coating-material and a damage on the mold are prevented, whereby in-mold coat-forming is stably performed for the long term.

Abstract: A mold closing device of an injection molding machine for producing plastic parts made of two or more plastic components includes a central mold carrier element which is arranged between two outer mold mounting plates and has two or four opposing mold mounting areas arranged in pairs for affixing two or four mold halves and which is fitted with a turning device supported in a supporting frame. Each of the mold halves of the mold carrier element can be closed against the mold halves of the outer mold mounting plates by a drive mechanism and a mold pressure unit. The outer mold mounting plates are interconnected by columns which extend through the supporting frame for the central mold carrier element. The supporting frame is fixedly connected to the machine frame while the outer mold mounting plate is displaceably supported on the machine frame.

Abstract: Disclosed herein are a method and apparatus for combining two or more streams of a polymeric material to form a plastic object. The method and apparatus are capable of ending an interior layer of the plastic object at a desired length to avoid the need to clean selected surfaces of components used to form the plastic object. The method and apparatus increase the velocity of the polymeric material used to form the plastic object in certain components used to form the plastic object. The increase in the velocity of the polymeric material facilitates the ending of the interior layer of the plastic object.

Abstract: Foamed molded articles can be produced during an injection molding process, among other things, by utilizing physical blowing agents. Existing technologies differ to the greatest possible extent in the manner how the blowing agent is introduced into the melt. One possibility is to supply the blowing agent via mixing elements (9) from porous or permeable material that are provided across the screw piston (1) and which by means of a suitable blowing agent input unit load and homogeneously charge the melt with blowing agent during the metering phase of the polymeric material. The resulting single phase polymer/blowing agent mixture, when injected in to an injection mold tool, produces due to a reduction in pressure, a foam-textured part.

Abstract: An injection molding shooting pot shot size control apparatus is configured to be installed in a coinjection hot runner with a coinjection nozzle, the coinjection nozzle having at least two melt channels ending at the same gate includes a valve inlet and a valve outlet. An adjustable melt control mechanism, preferably in the form of a hydraulically actuated wedge, is configured to (i) be disposed in a cavity plate adjacent to a hot runner assembly, and allow the shot size position to be set while the mold is open, and (ii) permit the charged shooting pot cylinder to decompress the melt when the wedge is pulled away from the shooting pot piston.

Abstract: Coinjection molding shooting pot cooling apparatus and method are configured to cool a shooting pot cylinder which, in combination with a shooting pot piston, injects a melt through a coinjection nozzle having at least two melt channels ending at the same gate. Preferably, a heat sink sleeve is disposed to contact an outer surface of a rear portion of the shooting pot cylinder. The heat sink sleeve is configured to remove sufficient heat from the shooting pot cylinder to increase the viscosity of the melt therein, thus reducing melt leakage between the shooting pot piston and the shooting pot cylinder.

Abstract: A nozzle for an injection molding machine is disclosed. The nozzle includes a nozzle body, an inner nozzle, and an outer nozzle. The nozzle defines two independent flow paths therethrough. The nozzle can simultaneously discharge two materials. A method of using the nozzle and a resulting golf ball product are also disclosed.

Abstract: A resin molding device, resin molding method and resin molded product capable of guiding a sink to an optional position to perform a precise molding. A resin molding metal mold includes a gate formed in the central part of a cavity, a stepped part increasing the opening diameter of the cavity in the circumferential direction orthogonal to the flowing direction of a molten resin introduced into the cavity from the gate, and a fine outside air inlet part circumferentially formed on the outer part from the stepped part. The outside air inlet part is formed of a porous material and allowed to communicate with the outside of the resin molding metal mold through a communicating passage.

Abstract: A method for solid free-form fabrication of a three-dimensional metal object includes depositing a particulate blend in a defined region, the particulate blend including a number of metal or metal alloy particulates and a peroxide, and selectively ink-jetting a binder system onto a predetermined area of the particulate blend to form a green part, wherein the liquid phase binder includes a water soluble monofunctional acrylate-based monomer, a water soluble difunctional acrylate-based monomer, an amine, and water.

Abstract: A horizontal multi-material molding machine includes a rotary table having a rotation axis center in a horizontal direction, a multi-material molding metal mold mounted on the rotary table, injection plunger units disposed to advance to and retreat from the multi-material molding metal mold for injecting a molten resin into cavities of the multi-material molding metal mold, a servo motor for rotating the rotary table, and a brake mechanism mounted on the servo motor and actuated when the servo motor is stopped for maintaing the position of the rotary table.

Abstract: A resin roller (10) is produced by disposing a core body (21) in a forming metal mold (1) having a cylindrical metal mold (13) and core supporting members (14) furnished at both edge parts of the cylindrical metal mold (13) as well as causing the core supporting members (14) to hold said both edge parts, and pouring a forming resin into the metal mold and solidifying it. The resin roller (10) has the core body (21) of the same outer diameter over a full length and a cylindrical resin-formed body (12), sealing members (24, 26) are furnished around the core body (21) in the vicinity of both edge parts of the resin-formed body (12), and the core body (21) is disposed such that the sealing members (24, 26) contact edge faces (14a) at sides of a roller forming space of the core supporting members (14).

Abstract: Manufacturing a coating for an impression cylinder whereby a carrier and a cylinder shape is provided. A hollow cylinder is positioned between the carrier and the cylinder shape, and material to form the coating in the spaces is introduced between the carrier and the hollow cylinder (the internal field) and between the hollow cylinder and the cylinder shape (the external field). The hollow cylinder is removed at a certain pre-selected velocity from between the carrier and the cylinder shape.

Abstract: An apparatus and method for injection molding of molded products including a first cavity chamber for forming a seal liner, with the first cavity chamber having an outer edge, and a second cavity chamber for forming a shell, with the second cavity chamber having a center and being adjacent to the first cavity chamber. The injection molding apparatus and method also includes a first nozzle for a seal liner material positioned near the outer edge of, and in communication with, the first cavity chamber, and a second nozzle for a shell material positioned near the center of, and in communication with, the second cavity chamber. The injection molding apparatus and method further includes a mold core capable of being positioned in and moved between the first and second cavity chambers.

Abstract: Coinjection molding nozzle apparatus and method includes structure and/or steps whereby a first nozzle melt channel is kept thermally separated from a second nozzle melt channel. Preferably, grooves in the nozzle body or a separate nozzle pipe keep the first and second nozzle melt channels thermally separated. Preferably, a highly thermally conductive nozzle tip is removably coupled to the nozzle body and includes first and second nozzle tip melt channels that merge together before the mold gate.

Abstract: A mechanical shut-off valve member for use with gas-assisted injection molding systems. A piston member is slidingly positioned in a body member or housing and spring-biased to a closed position. The valve member is opened by the injection of plastic material through the valve member and into a mold cavity. The spring biasing force closes the valve member and shuts off the flow of plastic once the mold cavity is filled with the requisite amount of plastic material. The shut-off valve member prevents any backflow of plastic material into the nozzle or injection molding machine during further steps in the injection molding process, including injection of gas or fluid into the plastic in the mold cavity.