Abstract: An injection molding system having an improved valve gate arrangement that provides molded articles with improved vestige and or surface quality.

Abstract: An improved positive control non-return valve assembly which is mounted on the front end of a helical plasticating screw of an injection molding machine. The valve assembly comprises a thread retainer with means for attachment to the plasticating screw. The valve assembly also comprises a distribution chamber that has an annular shaped flow gap and a cylindrical passageway that leads to a plurality of discharge ports. The non-return valve assembly forms a seal, builds pressure, and displaces molten plastic fluid from the distribution chamber through a discharge chamber passageway, and into a mold.

Abstract: An injection molding machine includes a plasticating unit for plasticating a thermoplastic resin, and an injecting unit connected to the plasticating unit through a connecting passage to inject the plasticated resin into a mold. The injecting unit A includes a rotary pump having a suction port connected to the plasticating unit through the connecting passage and a discharge port connected to the mold. The plasticated resin is intermittently injected into the cavity of the mold through the injection port by means of the rotary pump. In the connecting passage, an accumulator is provided which reserves the resin plasticated in the plasticating unit in an amount equal to or more than the shot capacity, and feeds the resin to the rotary pump.

Abstract: An injection nozzle for mixing heads of reaction molding machines is disclosed which comprises a housing in which a adjustment assembly is provided for slidably moving between two adjustable stops, wherein the adjustment assembly is configured as a control sleeve which includes a pressure chamber with a movable control piston disposed therein and the pressure chamber can be impinged upon by a pressure medium, for example hydraulic fluid and wherein a first stop is provided for the control sleeve and a second stop is provided for the control plunger thereby permitting an adjustment of two operating points that are exactly reproducible, so as to prevent disturbances during operation of the molding process.

Abstract: A leak preventing device for fluid shooting nozzle of an injection molding machine includes a material stop valve pivotally screwed with a front side of a vertical flow passageway of a hot-material passageway plate, a shaft position base provided at a rear side of the vertical flow passageway, a shaft inserting through the stop valve, the vertical flow passageway and the shaft position base, and a material stop end at front end of the shaft supported by a support plate in the material stop valve. The rear end of the shaft protrudes out of the shaft position base and connected to a piston fixed with a mold fix plate for mutual movement to lot the stop end of the shaft rod fitting in a shooting nozzle in the stop valve to prevent raw material inside from leaking out. Besides, after a screw conveying tube shoots out raw material, the remaining pressure in a flow passageway will push the leak-preventing portion to prevent leaking.

Abstract: In an injection molding machine having first and second nozzles for delivering melt material from a common manifold to one or more mold cavities, apparatus for controlling delivery of the melt material from the nozzles to the one or more mold cavities, each nozzle having an exit aperture communicating with a gate of a cavity of a mold and being associated with an actuator interconnected to a melt flow controller, the apparatus comprising a sensor for sensing a selected condition of the melt material through at least one of the nozzles; an actuator controller interconnected to each actuator, each actuator controller comprising a computer interconnected to a sensor for receiving a signal representative of the selected condition sensed by the sensor, the computer including an algorithm utilizing a value corresponding to a signal received from the sensor as a variable for controlling operation of an actuator for the at least one nozzle; wherein the melt flow controller controls the rate of flow of the melt materi

Abstract: An injection molding apparatus and method are provided in which the rate of material flow during an injection cycle is controlled. According to one preferred embodiment, an injection molding apparatus is provided that includes a manifold, at least one injection nozzle coupled to the manifold, an actuator, and a valve pin adapted to reciprocate through the manifold and the injection nozzle. The valve pin has a first end coupled to the actuator, a second end that closes the gate in a forward position, and a control surface intermediate said first and second ends for adjusting the rate of material flow during an injection cycle. Retracting the valve pin tends to decrease the rate of material flow during the injection cycle and displacing the valve pin toward the gate tends to increase the rate of material flow during the injection cycle.

Abstract: Injection mold for manufacturing disc-shaped plastic objects with a central hole, which mold comprises: a first mold part; a second mold part displaceable relative to this first mold part; which two mold parts are displaceable between a closed first position, in which they together partially bound a mold cavity corresponding to the shape of an object for manufacture, and an open second position in which a formed object can be removed; a third mold part which in an active position extends through the mold cavity and in the region of this mold cavity has a shape corresponding to the shape of the central hole, which third mold part is axially displaceable relative to the first and second mold parts between said active position and a retracted rest position; which third mold part bounds with the guide sleeve a channel which is connectable to the injection nozzle of an injection molding device, which channel can be opened and closed by means of a valve consisting of a valve seat which is formed by a part of the in

Abstract: An injection device includes a cylinder, a plunger and a driving device. The cylinder has a port for supplying molding material into the cylinder, and the molding material supplies into the cylinder is compressed by the plunger. The plunger has a groove extending circumferentially around an outer wall of a large-diameter portion of the plunger, and the clearance between the outer wall of the large-diameter portion of the plunger and the inner wall of the cylinder is determined by a specified equation.

Abstract: An improved injection molding runnerless manifold and nozzle system, method and apparatus in which the fluid plastic molding material transfer conduits, such as the manifold runner channels and cavity injection nozzle passageway, are constructed of a low thermal conductivity, non-metallic heat insulation structural material to thereby heat insulate the liquified molding material or resin, whether thermosetting or thermoplastic, while resident in the manifold runners and/or nozzle passageways. The heat transfer and other physical parameters of the conduit material and structure are such that this molding material remains at a reasonable uncured molding temperature while resident in the transfer conduit for the duration of at least one injection cycle due to the heat insulation characteristics of these fluid flow conduits of the system.

Abstract: A valve pin actuator is disclosed that includes a cylinder mounted to the clamping plate, a piston slidably mounted in the cylinder, and a valve pin assembly carried by the piston. A hydraulic or pneumatic circuit is provided for controlling the movement of the piston, and in turn translation of the valve pin between the seated and unseated positions. The valve pin assembly includes a first part removably secured to the piston so as to translate therewith, and a second part for receiving the valve pin and secured to said manifold. The actuator assembly enables removal of the clamping plate without removal of the valve pin assembly, and also adjusting of the valve pin without removal of the clamping plate. The assembly further provides a clearance between the piston and valve pin assembly, to accommodate expansion and movement of the manifold that would otherwise cause a side load to be exerted on the valve pin.

Abstract: In an injection molding machine having first and second nozzles for delivering melt material to first and second mold cavities of first and second molds respectively, apparatus for controlling delivery of the melt material from the nozzles to the mold cavities, each nozzle having an exit aperture communicating with a gate of a cavity of a respective mold and being associated with an actuator interconnected to a melt flow controller, the apparatus comprising a sensor for sensing a selected condition of the melt material through at least one of the nozzles; an actuator controller interconnected to each actuator, the actuator controller interconnected to the actuator associated with the at least one nozzle comprising a computer interconnected to the sensor, the computer receiving a signal representative of the selected condition sensed by the sensor, the computer including an algorithm utilizing a value corresponding to a signal received from the sensor as a variable for controlling operation of the actuator for

Abstract: The present invention provides a process for fluid assisted injection molding comprising the step of providing an injection molding apparatus having a mold body that defines a mold cavity. The process further comprises the steps of supplying a quantity of fluent plastic to the mold cavity, followed by injecting a fluid into the mold cavity. The fluid forms an expanding fluid pocket in the mold cavity, driving plastic to the furthest recesses of the mold and ensuring a smooth surface finish of the final molded product. A reservoir is selectively connectable to a plastic injection runner, and can be opened to the runner to receive molten plastic ejected by the introduction of the fluid to the mold cavity. When the reservoir is thusly connected, the pressure of the fluid forces the plastic through a supply passage, in a direction substantially opposite to its initial injection direction.

Abstract: An apparatus and method for injection molding includes a first melt passage for the flow of a first material, and a second melt passage in communication with the first melt passage for the flow of a second material. The apparatus and method for injection molding also includes a valve pin that passes through the second melt passage. The valve pin has a first portion allowing the flow of the second material, but not the first material, through the second melt passage, and a second portion restricting the flow of the first material and the second material through the second melt passage. The valve pin may also be used to restrict material flow from a melt channel into a cavity. In addition, a back-flow control valve may be combined with a melt passage of the apparatus and method for injection molding. The back-flow control valve has a first portion for permitting flow of material through the melt passage, and a second portion for restricting flow of material through the melt passage.

Abstract: An injection molding device (1) including an actuating cylinder (15) with a piston (33). A valve pin (11) is actuated by the cylinder (15), the piston including a fluid passage (55) via which pressure medium can pass when the piston is in a position between its upper and its lower end position, and which is at least partly closed off when the piston is in its lower and/or its upper end position. Hereby relatively simple position indicator of the valve pin (11) is formed.

Abstract: The invention is an apparatus for mixing and injection molding thermosetting polyurethane. The invention involves using a premixer comprising of a series of specially designed premixing chambers, one or more static, rather than dynamic, mixers, and a specially designed dual-path mixer. After the material is mixed it is pumped into an injector, and then deposited into a mold. This entire process is accomplished in an airtight environment. The mold into which the material is pumped is attached to a vacuum that decreases the chances of any air bubbles being trapped inside the mold. New features of the apparatus include a dual-path mixer and a newly designed premixing chamber.

Abstract: A leak preventing device for fluid shooting nozzle of an injection molding machine includes a material stop valve pivotally screwed with a front side of a vertical flow passageway of a hot-material passageway plate, a shaft position base provided at a rear side of the vertical flow passageway, a shaft inserting through the stop valve, the vertical flow passageway and the shaft position base, and a material stop end at front end of the shaft supported by a support plate in the material stop valve. The rear end of the shaft protrudes out of the shaft position base and connected to a piston fixed with a mold fix plate for mutual movement to let the stop end of the shaft rod fitting in a shooting nozzle in the stop valve to prevent raw material inside from leaking out. Besides, after a screw conveying tube shoots out raw material, the remaining pressure in a flow passageway will push the leak-preventing portion to prevent leaking.

Abstract: A mold for molding a thermoplastic resin comprising a pair of a male mold and a female mold in that a molten mass of a thermoplastic resin is supplied into a molding cavity formed by the male and female molds through a conduit for a resin melt, and after the completion of the supply of the resin, the supplied resin is shaped while shutting off the conduit for a resin melt with a pin for opening and closing the conduit for a resin melt, in which the conduit has a through-mouth of a nozzle, and a warmed conduit connected with the upstream side of the through-mouth, and the mold has a movable pin for opening and closing the conduit for a resin melt, the first heater to heat the wall of the conduit for a resin melt, and the second heater to heat the through-mouth.

Abstract: An injection molding device (1) having a valve pin (11) and an actuating cyclinder (15) connected to the valve pin (11). The valve pin head (37) is releasably attached to the piston (33) of the cylinder such that the cylinder can be removed while leaving the valve pin (11) from the nozzle such that a low headspace can be achieved above the nozzle.

Abstract: A molding nozzle controls the flow of material from a source of plastic melt to an outlet that communicates with a gate to a mold cavity. The nozzle contains a valve pin that includes a guide section and a valve end, and is movable toward and away from the gate to open and close the gate selectively. The valve pin is guided for movement by guide surfaces on inwardly-extending vanes within the nozzle, such that the guide surfaces engage the guide section of the valve pin. The valve end of the valve pin has a smaller diameter than that of the guide section, so that the valve section is free-floating to allow annular flow in the guide surface region to minimize the likelihood of formation of flow lines in the molded part.

Abstract: A valve pin actuator is disclosed that includes a cylinder mounted to the clamping plate, a piston slidably mounted in the cylinder, and a valve pin assembly carried by the piston. A hydraulic or pneumatic circuit is provided for controlling the movement of the piston, and in turn translation of the valve pin between the seated and unseated positions. The valve pin assembly includes a first part removably secured to the piston so as to translate therewith, and a second part for receiving the valve pin and secured to said manifold. The actuator assembly enables removal of the clamping plate without removal of the valve pin assembly, and also adjusting of the valve pin without removal of the clamping plate. The assembly further provides a clearance between the piston and valve pin assembly, to accommodate expansion and movement of the manifold that would otherwise cause a side load to be exerted on the valve pin.

Abstract: An elongate projection or probe extends from the injection unit of an injection molding apparatus. A passage extends through the projection in fluid communication with the injection unit. A generally cylindrical receptacle is formed in a portion of the mold of the injection molding apparatus for receiving the projection in generally concentric sliding relation. The receptacle is in fluid communication with the mold cavity, wherein relative movement between the projection and the receptacle causes injection unit to be selectively in fluid communication with the mold.

Abstract: The present invention relates to an in-mold gate opening and closing mechanism in which it is easy to adjust the gate balance, more specially, in an in-mold gate opening and closing mechanism, in which a gate pin disposed in a gate in a mold is moved in line with resin pressure in the gate, the gate is opened by the gate pin escaping from the gate when the resin pressure exceeds an appointed pressure level when filling resin, and the gate is closed by the gate pin moving the gate direction when the resin pressure is lowered from the appointed pressure level when a filling of the resin is completed, wherein the gate is opened by a gate pin escaping from the gate when the resin pressure exceeds a pressing force of a spring adjusted by a mechanism for adjusting the spring pressure when filling resin, and the gate is closed by the gate pin moving in the gate direction by a pressing force of the spring adjusted by the mechanism for adjusting the spring pressure when the resin pressure is lowered below an appointed

Abstract: A mold bushing for injecting plastic material into a mold cavity. The bushing member has a one-piece body member with a central passageway for a shut-off gate pin member and a separate and distinct passageway for the molten plastic material. In one embodiment, a tip member is positioned on the end of the body member and has a material discharge chamber. A gate or orifice opened and closed by the pin member is positioned either in the tip member or the mold. A wear bushing member can be positioned in the discharge chamber or the end of the body member to support the end of the pin member and prevent the flow of plastic material into the central passageway. The body member is heated by an annular cast heater member or the like. In an alternate embodiment, the body member has an extension which partially fills the discharge chamber and the wear bushing is a cylindrical member positioned at the discharge end of the central passageway.

Abstract: A valve gating apparatus for injection molding including at least one shutter disposed between the gate and the cavity melt channel into a mold cavity. The shutter is removably fastened to a rail member. When the rail member is moved laterally, the shutter moves between a closed position wherein flow of melt from the nozzle into the cavity is inhibited, and an open position wherein flow of melt into the cavity is unimpeded by the shutter.

Abstract: A pressurized-fluid-operated actuator has two piston surfaces for providing increased output force. The actuator includes a hollow piston that is divided into two inner chambers by a stationary inner dividing wall that is rigidly connected with a cylinder end wall. The piston has an outer diameter that is smaller than the inner diameter of the cylinder, and the piston carries three axially spaced sealing rings that define two axially-spaced annular chambers between the piston and the cylinder. Each of the annular chambers is in fluid communication with a respective port provided in the cylinder wall. Introduction of pressurized fluid into one port causes the fluid pressure to act on a single piston surface to retract the piston and rod, and introduction of pressurized fluid into the other port causes the fluid pressure to act on two axially-spaced piston surfaces to provide an increased output force without increasing the diameter of the cylinder and piston and without increasing the pressure of the fluid.

Abstract: Improved hot runner valve gate piston apparatus and method includes structure and steps whereby the air piston cylinder wall transmits less than all of the compressive force between the backplate and the manifold. Preferably, a backup pad is disposed in contact with the manifold and the backplate, for transmitting some of these compressive forces. Preferably, the backup pad also transmits heat from the backplate to the manifold, reducing the temperature of the cylinder wall. A flex member is preferably provided adjacent to or integral with the cylinder for absorbing some of the compressive forces between the backplate and the manifold, and in order to maintain the air seal between the piston cylinder in the air channel in the hot runner backplate.

Abstract: An injection molding apparatus is provided for controlling the rate of material flow into a mold cavity or plurality of mold cavities during an injection cycle. The apparatus is, for example, a hot runner system for injecting plastic melt. A valve pin is provided for controlling the flow of material away from the gate. A gap is formed between the surface of the valve pin and the surface of the material flow bore away from the gate. Control of material flow is achieved by displacing the valve pin and thereby adjusting the size of the gap. A control system is provided that compares a sensed condition indicative of the rate of material flow into the mold cavity to a target profile of the sensed condition, and adjusts the valve pin during the injection cycle to mirror the target profile.

Abstract: An open injection-molding nozzle (1) is provided having a needle (2) which can be moved in its longitudinal direction within the nozzle (1) in the direction of its tip (3). The needle (2) can be retracted such that between the opening (4) leading into the mold or its cavity and this needle tip (3), annular slots of different size can be formed in adaptation to the current injection-molding phase or the process of opening of the mold.

Abstract: A valve pin assembly for an injection molding apparatus comprising a valve pin capable of movement up and down in a nozzle to open and close a ring gate. An annular passage is created through the nozzle and is unobstructed and without restriction at all points up to and through the ring gate, permitting melt to flow freely to the gate and, depending on the position of the valve pin, into the mold cavity. The valve pin has a head with a diameter larger than the valve pin shaft for selectively closing the gate. The ring gate channel diameter is larger than the melt channel diameter to permit parts with large apertures therein to be formed.

Abstract: Sprue gated injection molding apparatus for molding preforms or other products having two layers of a barrier material such as EVOH or nylon alternating between three layers of another thermal plastic material such as PET. The PET is injected by one injection cylinder into first and third melt passages which branch in a front melt distribution manifold to extend to a number of heated nozzles. The first melt passage extends through a central melt channel in each heated nozzle and the third melt passage extends through an outer annular melt channel surrounding the central melt passage to an aligned gate leading to a cavity. The barrier material is injected by another injection cylinder into a second melt passage which branches in a rear melt distribution manifold to extend to an inner annular melt channel extending between the central melt passage and the outer annular melt channel in each heated nozzle.

Abstract: An injection molding apparatus is provided in which the rate of material flow during an injection cycle is controlled. According to one preferred embodiment, an injection molding system is provided that includes a manifold adapted to receive material injected from an injection molding machine and distribute the material to a plurality of channels, a plurality of injection molding nozzles coupled to the manifold, each injection molding nozzle having a bore for passing material from one of said channels of the manifold to a respective gate of a respective separate mold cavity, and a controller to individually control respective rates at which material flows into each separate mold cavity during an injection cycle.

Abstract: Improved hot runner valve gate piston apparatus and method includes structure and steps whereby the air piston cylinder wall transmits less than all of the compressive force between the backplate and the manifold. Preferably, a backup pad is disposed in contact with the manifold and the backplate, for transmitting some of these compressive forces. Preferably, the backup pad also transmits heat from the backplate to the manifold, reducing the temperature of the cylinder wall. A flex member is preferably provided adjacent to or integral with the cylinder for absorbing some of the compressive forces between the backplate and the manifold, and in order to maintain the air seal between the piston cylinder in the air channel in the hot runner backplate.

Abstract: An injection molding apparatus is provided in which the rate of material flow during the injection cycle is controlled. According to one preferred embodiment, an injection molding apparatus includes a manifold having an inlet for receiving material injected from an injection molding machine, a plurality of injection nozzles coupled to the manifold for distributing the material to a corresponding plurality of gates to one or more mold cavities, and a plurality of sensors respectively associated with each of said plurality of nozzles, each sensor to sense a condition related to the rate of material flow at a location between said inlet and said plurality of gates.

Abstract: A valve gating arrangement for an injection molding system having an insulated manner and a heated torpedo across from a gate. The valve gating arrangement includes a valve member sidably received within a passage extending through the torpedo. The valve member terminates at one end with a pin reciprocally movable into and out of the gate. An actuator is connected to the valve member to effect the reciprocal movement.

Abstract: A vibration applying apparatus associated with an injection molding machine for applying vibrational repetitive movements to a melt of molding materials includes a rod having a tip end received inside a heating cylinder and disposed in the proximity of a nozzle of the heating cylinder, a stationary guide supporting the rod such that the rod is movable back and forth, a rotating shaft being orthogonal to the rod, a drive motor for rotating the rotating shaft, and a cam mechanism acting between the rotating shaft and the rod so as to convert rotary motion of the rotating shaft into linear reciprocal motion of the rod. With the apparatus thus arranged, the tip end of the reciprocating rod applies vibrational repetitive movements to the melt of molding material, thereby lower the viscosity of melt. The frequency of vibrational repetitive movements can be varied by changing the rotational speed of the drive motor.

Abstract: An injection molding nozzle tip thermal insulator includes an apparatus for removably fastening the insulator to a nozzle tip having a receiving detent therein. The apparatus includes a fastening structure that engages the nozzle tip receiving detent and holds the insulator onto the nozzle tip. The fastening structure is movable between a first position where the insulator is fastened to the nozzle tip, and a second position where the insulator is removable from the nozzle tip. Also included are a method of removably attaching the insulator to the nozzle tip, and assembly and removal tools for attaching and removing the insulator from the nozzle tip, respectively.

Abstract: In an injection molding machine having first and second nozzles for delivering melt material from a common manifold to one or more mold cavities, apparatus for controlling delivery of the melt material from the nozzles to the one or more mold cavities, each nozzle having an exit aperture communicating with a gate of a cavity of a mold and being associated with an actuator interconnected to a melt flow controller, the apparatus comprising: a sensor for sensing a selected condition of the melt material through at least one of the nozzles; and, an actuator controller interconnected to each actuator, at least one actuator controller comprising a computer interconnected to the sensor for receiving a signal representative of the selected condition sensed by the sensor, the computer including an algorithm utilizing a value corresponding to a signal received from the sensor as a variable for controlling operation of an actuator for the at least one nozzle.

Abstract: Injection molding apparatus having a removable nozzle seal (110) which screws onto the outside of the front end (76) of a heated nozzle (12). A mounting sleeve (98) having a threaded outer surface (104) is integrally mounted around the front end (76) of the nozzle (12). The nozzle seal (110) has a retaining portion (118) with a threaded inner surface (120) to screw onto the mounting sleeve (98) extending rearwardly from a central nut portion (112). A sealing and alignment flange portion (122) extends forwardly from the central nut portion (112) and fits into a cylindrical portion (124) of a well (14) in the mold (18) to accurately align the front end (76) of the nozzle (12) and prevent melt leakage between the heated nozzle (12) and the surrounding cooled mold (18). In another embodiment, a sealing and alignment portion (136) of the nozzle seal (110) extending forwardly into an opening (148) in the mold (18) forms the gate (90).

Abstract: In an injection molding machine, an apparatus for controlling movement of a pin comprising a plastic melt flow channel having an output end for delivering molten plastic injected into the channel under pressure to a mold cavity, wherein the pin comprises an elongated rod having an axis and an end, the pin being slidably mounted within the channel for movement along its axis within the channel, an electrically driven motor drivably interconnected to an actuating mechanism, wherein the actuating mechanism is drivably interconnected to the end of the pin, the motor being controllably drivable to drive the pin through movement along its axis within the channel

Abstract: In an injection molding machine having first and second nozzles for delivering melt material from a common manifold to one or more mold cavities, apparatus for controlling delivery of the melt material from the nozzles to the one or more mold cavities, each nozzle having an exit aperture communicating with a gate of a cavity of a mold and being associated with an actuator interconnected to a melt flow controller, the apparatus comprising: a sensor for sensing a selected condition of the melt material through at least one of the nozzles; and, an actuator controller interconnected to each actuator, at least one actuator controller comprising a computer interconnected to the sensor for receiving a signal representative of the selected condition sensed by the sensor, the computer including an algorithm utilizing a value corresponding to a signal received from the sensor as a variable for controlling operation of an actuator for the at least one nozzle.

Abstract: An injection moulding tool comprises a hot-runner manifold plate, at least one nozzle holder resting on said hot-runner manifold plate, a shut-off needle which is movably guided in said nozzle holder, and a piston arranged in a piston chamber and adapted to be actuated by a fluid, said piston being connected to the shut-off needle and moving said shut-off needle to its various positions. The hot-runner manifold plate comprises at least one distributor channel, the nozzle holder comprises at least one supply channel which is associated with the shut-off needle, and said at least one distributor channel is connected to said at least one supply channel. A structural design of this kind is to be simplified and rendered more compact. For this purpose, the piston chamber is integrated in the nozzle holder in such a way that the piston is arranged between the shut-off needle and the hot- runner manifold plate.

Abstract: A method and apparatus for runnerless injection molding of plastic materials utilizing a novel valve stem for controlling the opening and closing of at least two gates in a single injection nozzle The method and apparatus includes at least two separate melt streams whose flows are not obstructed by the valve stem. These melt streams may contain the same plastic material or different plastic materials and the injection nozzle may be either simultaneously or sequentially activated for filling the mold cavity.

Abstract: A valve-type nozzle (10) is provided for use in hot runner systems through which a plastic material melt is fed under high pressure to a separable and coolable tool having at least one mold cavity (K) for injection-molded items. The nozzle is heatable and comprises at least one needle valve (20) supported by sliding guides (28, 38), the arrangement being such that the melt, which is fed trough a material pipe (14), passes around at least a lower section (22) of the needle valve (20). The nozzle (10) further comprises, in an antechamber (30) upstream of the mold cavity (K), at least one outlet (18) adapted to receive a closely fitting needle end (24). The needle valve (20) includes in its lower section (22), upstream of the needle end, a pressure-relief arrangement that is in direct flow-connection with the antechamber (30).

Abstract: An injection molding machine is provided that includes a manifold for distributing plastic melt flow to one or more mold cavities. The manifold has a flow channel having an output orifice surrounded by a lower outside surface, and is expandable upon heating. The injection molding machine also includes a nozzle comprising a body mounted in a receiving aperture in a stationary housing aligned with a gate to a mold cavity, the body having a central bore for delivering plastic melt flow from the channel in the manifold to the mold cavity, the body having an upper surface for engaging with the lower surface of the manifold. The body has a lip member comprising an outer leg circumferentially spaced from an inner body section of the body, the outer leg having a surface mounted against a mounting surface of a stationary housing.

Abstract: A coinjection molding system for injecting skin and core material into a mold cavity. The system includes a three position actuator for moving a valve pin into a closed position in which neither skin nor core flow is permitted, a middle position in which only skin flow is permitted, and an open position in which skin and core flow is permitted. The actuator includes a first piston slidably mounted in an actuator housing, and a second piston, attached to the valve pin, slidably mounted within the first piston. A shut-off is provided in the manifold for preventing skin flow to a particular nozzle during sequential gating.

Abstract: An injection molding apparatus is provided in which the rate of material flow during an injection cycle is controlled. According to one preferred embodiment, an injection molding apparatus is provided that includes a manifold having an inlet for receiving material from an injection molding machine, at least one injection nozzle coupled to the manifold, an actuator, and a valve pin adapted to reciprocate through the manifold and the injection nozzle, the valve pin having a first end coupled to the actuator, a second end that closes the gate in a forward position, and a control surface intermediate said first and second ends for adjusting a rate of material flow during an injection cycle.

Abstract: Mold bushings or nozzles for gas-assisted injection molding processes are disclosed. The devices include movable shut-off mechanisms which selectively facilitate or prevent the passage of molten plastic material into mold cavities. One or more apertures, such as holes, openings, channels, slits, slots, and the like, are provided at or adjacent the end of the pin members or at the end of the devices. The apertures are thin or small and have dimensions which will allow the passage of gas and at the same time prevent the plastic material from plugging or clogging them.

Abstract: The present invention relates to an apparatus for manufacturing a substantially flat article, such as a smart card, having at least one substantially flat edge. The apparatus includes a mold for forming the substantially flat article, which mold includes an inlet gate for allowing molten plastic material to flow into a cavity space defined by the mold. The apparatus further includes a source of molten plastic material, a passageway communicating with the inlet gate and the source of molten plastic material, and a blade or pin for pushing residual plastic material in the passageway into the cavity space formed so as to form a side edge for the substantially flat article having substantially no gate vestige. A method for manufacturing the substantially flat article is also described.

Abstract: An injection nozzle for injection molding machines with a valve system having a piston movably positioned around the top end portion of a nozzle body. A guide slot is formed at the top end portion of the nozzle body, and movably receives a pin actuating bar, integrated with a valve pin-of the valve system, and so the pin actuating bar is vertically and precisely movable under the guide of the guide slot. The valve pin is thus precisely movable in the nozzle body in a linear vertical direction without failure. The nozzle is also preferably used for producing large-scaled products or small-scaled products, thus have an improved compatibility. The nozzle is preferably used in a stack molding process. In addition, even when a manifold thermally expands due to a high temperature molten plastic material and is undesirably changed in position, the valve system is continuously operated without being stopped, thus allowing the injection molding process to be continued for a lengthy period of time.