Abstract: A holding device (1) for injection molding mold halves (61.2) or their holders contains two displacement units (2.1, 2.2), on each of which a rotation unit (4.1, 4.2) is attached. On each rotation unit (4.1, 4.2) there are holders (5.1, 5.2). Into the space (d) between the two holders (5.1, 5.2) a die holder designed as a prism-shaped rotating block can be inserted. The die holder in the holding device (1) can be displaced in one direction (z) and can be rotated around a displaceable axis (42.1, 42.2), which is vertical to the one direction (z). The displacement units (2.1, 2.2) can be displaced relative to one another to permit rapid and easy changing of injection molding molds (62.1).

Abstract: Apparatus for producing thermoplastic injection-molded parts reinforced with long fibers, includes a compounder having two meshing screws rotating in a same direction for continuously generating a stream of melt of thermoplastic material reinforced with long fibers. Melt is alternatingly conducted to at least two piston and cylinder units for injection into at least one cavity of an injection mold at a suitable pressure. Each of the piston and cylinder units includes a cylinder and a differential piston movably received in the cylinder and dividing the cylinder into a feed chamber and an injection chamber, wherein the piston has a relatively greater piston surface, adjacent the injection chamber, and a relatively smaller piston surface, adjacent the feed chamber.

Abstract: An injection molding machine using a two-disk forming mold, in which two disk substrates molded simultaneously are made uniform without unbalance in weight. The injection molding machine uses a two-disk forming mold. The mold includes two disk molding cavities independent of each other, and resin inlets provided correspondingly to the cavities respectively. In the injection molding machine, molten resin is simultaneously injected and charged into the two cavities respectively by two plasticizing/injecting units independent of each other. The operations of the two plasticizing/injecting units are controlled to make the molten resin uniform to be charged into the two cavities.

Abstract: A method for injection moulding, comprising introducing, under pressure, a melt into a cavity (14) defined by two mould halves (10, 11) of a mould (6). The method is characterised by the steps of joining the mould halves (10, 11), for definition of said cavity (14), by moving at least one of the mould halves (11) along a first axis, and, by moving along a second axis extending transversely of said first axis, arranging a locking means (7) on the mould (6). The locking means (7) has locking surfaces (19) which grasp the mould (6) and its joined mould halves (10, 11), at least one locking surface (19) wedgingly engaging a complementarily designed surface (17) of the mould (6) to cause conversion of the force by which the locking means (7) is arranged on the mould (6), into a locking force for holding together the mould halves (10, 11) in their joined state. The present invention also concerns an injection moulding assembly as well as a mould for injection moulding assemblies.

Abstract: A shooting pot actuator for an injection molding machine having two plates carrying pusher rods for pushing against injection plungers within the shooting pots. The plates are mounted outside the mold and the clamp unit, and the pushers extend through bores in the stationary platen of the clamp unit to reach the injection plungers. The actuator reduces the cost and complication of mold design and production, and permits simplified adjustment of the injection plunger stroke.

Abstract: An apparatus and a method are disclosed for manufacturing an integral one-piece catheter having a tube and a hub. The method comprises feeding molten material into a mold having a mold cavity. A fluid such as a gas is injected into an inlet of the mold. This causes the cavity to eject the molten central region of the polymer through an exit channel. In one embodiment, a gas is injected into the hub portion of the cavity. In another embodiment, a gas is injected into the catheter portion of the mold.

Abstract: A simplified lost-core molding system that combines otherwise redundant features such as platens and hydraulic cylinders ordinarily found in separate core molding stations and product molding stations. The preferred system locates the core mold and the product mold between the platens of an injection molding machine and applies a common clamping force to the core mold and to the product mold.

Abstract: The present invention relates to stack mold carriers in an injection molding machine with a rotating turret. Services to the rotating turret are provided by a rotary union attached to the translating mold carrier at the turret's axis of rotation. Hence, services such as oil, water, air and electrical power are provided to the rotating turret thereby allowing the turret to rotate in either direction. The rotating turret is attached to linkages which open and closed the molds through connection to a moving and a stationary platen which interface with the rotating turret to form molded articles therein.

Abstract: A tool structure or tool insert has a runner system which includes at least one branching runner which branches in at least two directions forming at least a first pair of branch runners for receiving laminar flowing material for the formation of a product. Each branch runner is at a position in the runner system such that it receives material having significantly similar conditions from side-to-side of a bisecting plane of that runner which bisects the cross section of at least a portion of the length of that branch runner. This material also has dissimilar conditions from side-to-side of a perpendicular plane of each branch runner which is perpendicular to the bisecting plane of that runner with the perpendicular plane of each branch runner also bisecting the cross section of the same portion of the length of each branch runner that the bisecting plane bisects.

Abstract: A plastic trial lens having a grip portion gripped when the lens is set in trial frames for trial lenses, an injection molded product for making the trial lenses, and a mold assembly for molding the injection molded product are provided. In the injection molded product molded by means of the mold assembly in an injection compression molding machine, a grip portion and a liquid guided and collected area are molded simultaneously with a lens portion on a periphery of the lens portion. When the injection molded product is dipped into hard coat liquid, the hard coat liquid is guided in the liquid guided and collected area to drip down and the remaining liquid without dripping down is collected in the liquid guided and collected area, thereby forming a coating film of uniform thickness on the lens portion. The plastic trial lens which is integrally provided with the grip portion is finished after the liquid guided and collected area is removed.

Abstract: A multilayer tube shoulder and method for manufacture wherein a first material component is injected into a cavity (22) and then removed from the cavity on a support (12) while in a partly-plastic state. Thereafter, following insertion of the first material component into a second cavity (23), a second material component is injected around the first material component, and thereby leads to a positive connection between the first and second material components.

Abstract: An injection press for molding pieces of elastomer comprises a fixed platen, a moving platen, and a turret carrying a plurality of molds, the turret and the molds being interposed between the two platens so as to be capable of being clamped between them in order to close the molds, and the turret being mounted to rotate so as to move each mold sequentially between an injection station, vulcanization stations, and an unmolding station. The press also comprises an injector device adapted to inject elastomer into each mold while it is in the injection station, heater devices adapted to heat the molds, and a control device adapted to move the moving platen and to cause the turret to turn.

Abstract: A tapered running block and corresponding tapered cavity blocks are utilized in a mold for fabricating relatively thin, flat plastic cards, such as used for pre-paid telephone cards and the like. The mating surfaces of the runner block and the cavity block are angularly tapered; so that metal-to-metal contact is made between the runner block and the cavity block when the mold is in the plastic injection position. As soon as relative movement of the runner block and the cavity block is effected to part the blocks and separate the cards from the runners, the tapered 1surfaces move away from one another without any sliding contact, thereby significantly reducing wear in the mold.

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: A method and apparatus for producing a contact lens material having two opposite lens-forming surfaces is disclosed. A first resin mold having a molding surface providing one of the opposite lens-forming surfaces of the contact lens material is injection-molded by closing a first and a second die to define at least one mold cavity and injecting a resin material into the mold cavity. A second resin mold having a molding surface is injection-molded by closing a third and a fourth die to define at least one mold cavity and injecting a resin material into the second mold cavity. The dies are separate away from each other and molding material is introduced into one of the resin molds which are held on one of the respective dies. The dies holding the first and second resin molds are moved relative to each other to assemble the first and second resin molds to define a mold cavity for the contact lens material.

Abstract: A process for formation of a plastic composite includes providing a two part mold system wherein one of the parts is moveable and includes cavities and the other of the parts is stationary and includes cores each having less mass and sequentially moving the moveable mold part with respect to the stationary mold part to form an injection volume between each of said mold cavities of variable capacity.

Abstract: A runner system and runner component particularly adapted for use in multiple cavity injection molding systems is disclosed. The runner system and runner component utilize particular structural features and geometrical configurations that have been found to result in superior molding practices and molded components in multiple cavity injection molding systems. A corresponding multiple cavity injection molding system utilizing the noted runner system is described. And, a related method for promoting uniform filling of multiple mold cavities is also disclosed.

Abstract: A tool for multi-component injection molding of plastic toothbrush bodies 4 for toothbrushes has two tool halves 1, 1′which can be opened and closed. In one tool half 1 a linearly movable transfer device 6 is arranged. The hollow mold spaces 2 for injection molding the first component are formed exclusively by the two tool halves 1, 1′. For transferring the injection-molded blanks (3) in the second station, the transfer device 6 moves into the area of the injection-molded blanks 3, picks them up by vacuum suction cups 11, and transfers the injection-molded blanks 3 by linear movement into the second station.

Abstract: A melt transfer system is provided for a stack mold. The melt transfer system includes first and second transfer bushings arranged in opposing platens of the mold. Each transfer bushing defines a portion of a runner passage communicating at shear gates disposed in a shearing surface that is parallel to the direction of opening and closing movement for said platens in order to shear the melt when the platens are moving from a closed position to an open position. In another aspect, the shearing surfaces are normal to the direction of movement of the platens and at least one of the transfer bushings is rotatable relative to the platen for shearing the melt. In another aspect, a transfer bushing is provided having a core formed of an insulative material and a shell formed of a conductive material. The core defines a channel for conducting melt between a shear gate at one end of the channel and an aperture at another end of the channel.

Abstract: A mold assembly designed for casting a layer for a golf ball is disclosed herein. The mold assembly has two halves that each hold a plurality of mold inserts. Each mold half is composed of a carrier base, a carrier plate, a retainer plate and a plurality of mold inserts. The multiple component aspect of each mold half allows for a more efficient transfer of heat during a casting process. Preferably, the mold assembly is utilized to mold a polyurethane cover on a golf ball precursor product.

Abstract: There is provided an apparatus for manufacturing lenses for vehicle lamps, wherein the lenses are formed from at least first and second types of synthetic resins by molding the first and second synthetic resins integrally with each other. The apparatus includes a first mold having a common mold and a first stationary mold and defining a first cavity in which the first synthetic resin is injection molded, and a second mold constructed from the common mold and a second stationary mold and defining a second cavity in which the first synthetic resin and the second synthetic resin are molded integrally with each other with the first synthetic resin being contained within the second cavity. A partition wall is provided on the first stationary mold in such a manner as to protrude therefrom for preventing the first synthetic resin from intruding into any place other than the first cavity when the first mold is closed.

Abstract: A nozzle end is provided for removable mounting to a nozzle body for use in multiple-tipped molding applications such as edge-gated systems. The nozzle end is made of a highly thermally conductive material and is preferably inserted at least partially inside the forward end of the heated nozzle body. Removable nozzle tips are insertable in the front end of the nozzle end.

Abstract: The present invention relates to a sprue bar assembly for use with a number of different injection molding machines. The sprue bar assembly comprises a fixed sprue bar section having a first channel through which molten material, such as a plastic resin, flows. The first channel communicates with the outlet of a source of the molten material. The sprue bar assembly further comprises an adjustable sprue bar section having a second channel through which molten material flows and a powered unit for holding the adjustable sprue bar section in contact with the fixed sprue bar section so that molten material can flow from the first channel to the second channel without leaking and for changing the length of the sprue bar assembly as needed to accommodate molds of different shutheights.

Abstract: The invention is a mold apparatus for making multi-component products. The apparatus includes an elongate turret, a plurality of product connection pairs attached on opposite sides of the turret, a first mold disposed proximate to the turret and a second mold disposed on the opposite side of the turret. The first mold has a plurality of cavities for molding a first molded layer of the multi-component product, and the second mold has cavities for molding a second layer onto the first molded layer. The turret is rotatable between the first mold and the second mold by rotation about its longitudinal axis of the turret.

Abstract: An injection mold is provided for injection molding an encapsulation material to encapsulate at least one integrated circuit chip. The injection mold includes at least two parts that define at least one injection circuit, and at least one blind complementary channel communicating with the injection circuit. The injection circuit includes at least one injection cavity for housing the chip, at least one transfer chamber from which the encapsulation material is injected, and at least one injection channel connecting the transfer chamber to the injection cavity. The blind complementary channel is formed between the two parts of the mold and forms at least one appendage of encapsulation material that is connected to the encapsulation material that fills the injection circuit. Also provided is a method for injection molding an encapsulation material to encapsulate at least one integrated circuit chip.

Abstract: In a part connecting member made from synthetic resin, at least two molded pieces obtained by the injection molding of plastic are provisionally connected by being adjacently arranged or abut against each other. The provisionally connected body is set in a die different from the dies used for the formation of each molded piece. Then, in a state such that each molded piece and the die are positioned, the molded pieces are joined by the injection of a molten resin material for joining into a gap formed between the opposed surfaces of the molded pieces that are adjacently arranged or abut against each other. An injection channel of the molten resin up to the gap is formed by using one of the molded pieces forming the gap of the opposed surfaces that are adjacently arranged or abut against each other.

Abstract: A cord wrap with integrally molded light holders and mold and method of making same is disclosed. The light holders are molded in cavities connected by runners. The runners are shaped and positioned to form a cord wrap. After the light holders are broken away from the runners, the runner can be used as a cord wrap to store strings of decorative lights such as those which were held by the light holders.

Abstract: A drool control apparatus having a piston disposed in a melt passage of a mold. The piston is moveable between a bypass position, where pressurised melt is permitted to flow past the piston to at least one nozzle, and a compression position, where the melt downstream of the piston is decompressed to inhibit drool at the nozzle.

Abstract: This invention relates to a mold design, injection molding machine and a method for forming a multi-layer plastic article by over molding where the second layer of the article includes a portion having a different geometrical profile than the first one. The novel injection mold and injection molding machine for producing over-molded articles comprises an array of one or more cores which engage arrays of one or more first cavity and arrays of one or more composite cavities. Each composite cavity is formed from the combination of a second cavity and a cavity extension which carries at least a portion of the different geometrical profile, such as a thread. In one embodiment, the cavity extension comprises a pair of cavity portions which are mounted adjacent the core to laterally moveable slides on a movable plate, that can be a stripper plate.

Abstract: The present invention relates to a plate type of continuous injection mold machine consisting of several forming plates for injection that are arranged upright and parallel to one another on an elongated frame. Each forming plate has hollow mold inside. When the plates are pressed to be adjacent to one another and the material is injected via the inlet pipe, the material such as pulp and plastics will fill up all space of the forming plates. As the injection of material continues, the material will be pressed and hydrated. When the forming plates are separated, a large number of molded products will be obtained simultaneously.

Abstract: A molding device is provided for the manufacture of a connector. Two mold halves are provided movable relative to one another, which provide molding spaces when the molds are closed for forming the connector housing and a retainer. One mold half includes a space with a core portion for forming a retainer insertion hole in the connector housing, and a retainer forming portion for forming the retainer in a position lateral of the core portion. The mold is also provided with inserting means for inserting the retainer into the insertion hole after the molding of the two pieces.

Abstract: A flash-free mold structure is designed for use in the molding of an encapsulant for encapsulating a semiconductor die. The flash-free mold structure includes a first molding piece and a second molding piece. The second molding piece is formed with a resin passage for an encapsulating material to flow therethrough during molding process. It is a characteristic feature of this flash-free mold structure that a cutaway portion, which can be either an one-step cutaway portion or a multi-step cutaway portion, is formed at the rim of the resin passage. The cutaway portion is dimensioned significantly smaller than the resin passage for the retarding the flow speed of the encapsulating material from the resin passage into the cutaway portion during the molding process, thereby preventing the encapsulating material from entering the fissure in the junction between the first and second molding pieces. The resin passage can be either a cull, a runner, or a subrunner defined by the first and second molding pieces.

Abstract: A molding and tentatively retaining mold 10 of the invention has a plurality of molds which are relatively movable with respect to a fixed mold, and molds a housing 31 and rear holders 32 and 33, which are respectively independent, in a plurality of cavities formed in cooperation with the fixed mold. When rear holders 32 and 33 after molding are relatively moved with respect to a housing 31 by movable molds 12 and 15 and are tentatively retained, a runner 20 for a cavity for molding the housing 31 is kept connected to the housing 31 through a tunnel gate 20a. In addition, a portion 15a of the fourth movable mold 15 for forming the cavity in the housing 31 is kept fitted to the housing 31 as it was during molding.

Abstract: A molding and tentatively retaining mold 10 of the invention has a plurality of molds which are relatively movable with respect to a fixed mold, and molds a housing 31 and rear holders 32 and 33, which are respectively independent, in a plurality of cavities formed in cooperation with the fixed mold. Diameters of runners serving as channels for the charging of a resin material into cavities of a molding and tentatively retaining mold are set for the respective cavities such that the charging of the resin material into the cavities is completed substantially at the same time.

Abstract: According to one aspect of the invention a method is provided for making a combination hub and catheter. A material is molded into a body having at least a first hub, and at least a first nose extending from the first hub. The first nose is then elongated into a catheter.

Abstract: An apparatus for molding hardenable material comprising a mold member having a cavity to receive hardenable material, a settling region for receiving a turbulated mix of hardenable material and a spout for discharging laminar flow into said cavity.

Abstract: An injection moulding unit includes at least two injection moulds for manufacturing disc-like objects. The injection moulds each further include two mould parts which are mutually displaceable between a closed position in which they bound a mould cavity and an opened position in which the disc-like object can be removed. The mould cavity is connected to a pressure line for carrying heated plastic into the mould cavity. A punching means is provided for punching a central hole through the disc-like object. The punching means includes a cylindrical part forming a portion of one of the mould parts and has a leading peripheral edge. The respective pressure lines of the injection moulds are branches of a feed line and together therewith form part of a collective multiple hot runner. The outlet zone of each feed line is configured to couple to an infeed of an injection bush. An outfeed of the injection bush debouches directly into the mould cavity.

Abstract: A tandem press has a moving frame comprising a moving platen moving in a reciprocating motion between stationary outer platens, between a first clamping position in which the moving platen clamps a first mold mounted on one side of the press, and a second clamping position in which the moving platen clamps a second mold on the other side of the press. The tandem press of the invention thus provides two complete clamping cycles within one press cycle. In the preferred embodiment the hydraulic pistons actuating the moving platen also serve as guide bars for maintaining the moving platen in alignment with the stationary platens. In the preferred embodiment the actuating cylinders are small bore diameter high speed cylinders, and the moving platen is provided with larger bore diameter hydraulic clamping cylinders to apply the required clamping force to the mold after the actuating cylinders have moved the moving platen to the clamping position.

Abstract: A molding apparatus for use in forming a flexible substrate based package comprises a plurality of pots. Two flexible substrates are installed at two sides of the pots. A plurality of sets of chips mounted on the upper surface of the substrate wherein each set of chips is in an array arrangement. The molding apparatus further comprises a plurality of runners. Each runner independently extends from one side of the pot to one side of the substrate, and connects to a cavity of a upper part of a mold disposed on the substrate through a gate. The present invention characterized in that, the molding apparatus is provided with a first communication channel formed corresponding to one side of the substrate and a second communication channel formed corresponding to the other side of the substrate. The first and the second communication channels interconnect the cavities at two opposite sides thereof.

Abstract: A universal mountable and demountable rack-and-pinion structure for a stack mold includes mounting plates affixed to the mold parts and rack-and-pinion mounting elements which are mountable to and demountable from the mounting plates. This arrangement permits the rack and pinion elements first to be mounted in an approximately correct position for the appropriate proportionation of movement within a molding machine. The device includes an adjustment feature which permits the relative distances between the mold parts to be finely adjusted to ensure correct proportionation of movement. The rack-and-pinion structure is interchangeable for various stack molds.

Abstract: Disclosed is a high pressure injection molding system employing one or more plastic injection molding workstations including split molds, a single plastic extruder coupled to a heated manifold capable of delivering fluid plastic to multiple workstations, and wherein final lockup of the split mold halves results in application of compressive forces effective to maintain the split mold halves in nominal position during high pressure injection molding conditions. Operational movement is performed by use of a single remote pumping station utilizing pressure compensated pumps, accumulators and manifolds. The independent mold workstations allow independent operation while providing efficency of operation for the hydraulic system and extruder system.

Abstract: A runner plate for an injection molding system comprises a plate typically having a plurality of corners, and typically apertures extending through the plate for receiving leader pins of the molding system for support of the plate in the molding system. Also at least a pair of outrigger supports may be provided, the outrigger supports being carried by the plate, each at a different position on the plate, and typically extending diagonally outwardly relative to adjacent plate edges. Also the outrigger support may carry rollers which are positioned to engage tie bars of the mold press for rolling contact therewith and support of the system.

Abstract: The present invention provides a method of forming proofed dough for baked goods in a predetermined shape, as well as an apparatus for practicing the method. The apparatus includes a closed dough handling system that includes a pressurized dough mixer, a dough transporting device joined to the pressurized dough mixer, and an injection molding device joined to the dough transporting device. The method includes the step of transporting proofed dough from the pressurized dough mixer through the dough transporting device to the injection molding device, wherein the injection molding device fills the injection mold with dough when it is connected to the dough transporting device, thus forming one or more pieces of dough having the predetermined shape within the molds. The injection molds containing the dough may then either be conveyed into an oven to form a baked piece of dough having the predetermined shape, or conveyed into a freezer to form a frozen piece of dough having the predetermined shape.

Abstract: A shooting pot actuator for an injection molding machine having two plates carrying pusher rods for pushing against injection plungers within the shooting pots. The plates are mounted outside the mold and the clamp unit, and the pushers extend through bores in the stationary platen of the clamp unit to reach the injection plungers.

Abstract: A method and apparatus for encapsulating one or more small electronic devices, including for example light-emitting diodes, mounted directly on a substrate by providing a three-dimensional formation on the substrate adjacent to the device and injection molding a thermoplastic encapsulating material to cover the device and extend over the three-dimensional formation on the substrate and wherein the encapsulating material mechanically bonds to the three-dimensional formation. A gate plate for use in injection molding a thermoplastic encapsulating material over a small electronic device mounted directly on a substrate including a cavity formed to enclose the device, and a short gate formed entirely within the gate plate having an input for receiving an encapsulating material and an output communicating with the cavity.

Abstract: A molding apparatus comprises a first mold plate positioned between a pair of second mold plates for opening and closing pairs of mold halves. The mold plates carry leader pins which are connected with each other in both the open and the closed position of the molding apparatus, for lateral support of the central first mold plate. Also or alternatively, a mold plate centering system is provided, comprising threaded rods carried by the first, central mold plate and pointing toward the second plates. Internally threaded sleeves are carried by the second plates, with at least a portion of each threaded rod occupying at least a portion of the bore of the internally threaded sleeve and screw threaded relation. Specifically, the threaded rods are joined together and freely rotatable, with the result that the position of the first, central plate is controlled as the respective plates are opened and closed by a moving platen of an injection mold.

Abstract: A device for molding a container having a first member including an opening defined therein. A manifold member, operatively attached to the first member for channeling a plastic fluid to an insert device is included. The insert devices are positioned within the opening located within the first member, with the insert containing a first slide and a second slide. The first slide and second slide will have an extended position and a contracted position, and wherein the contracted position defines a cavity profile. The second member will have a first end that contains a plurality of core pins. A piston is adapted to the second end of the second member for reciprocating the second member into engagement with the insert so that the first slide and second slide are moved to the contracted position. During the reciprocating motion, the plurality of core pins are received in the cavity profile. The apparatus will further comprise heater means for suppling a heat to the fluidized plastic.

Abstract: The present invention relates to stack mold linkages for creating unequal strokes for use in an injection molding machine for making different sized molded parts. The stack mold linkages comprise linkages for moving each of at least two mold assemblies between a mold closed position and a mold open position and for separating the mold halves forming the mold assemblies by unequal stroke lengths.

Abstract: A unitized heat conductive assembly 32 formed of a one piece heat conductive conduit 40 which permits shaping the heat conductive assembly as a continuous unit. The heat conductive assembly 32 is press fit into the heater block 12 configured so that it provides a predetermined flow path 14 for the flowable molten plastic materials to be delivered to the injector nozzles. There is provided a heat flow path 28 that follows the flow path 14. The heat conductive carrying conduit 40 is formed with an opening 42. The conductive conduit 40 is formed from a tubular piece of conductive metal such as copper or brass by a swaging process which forms a tubular structure 40 in a continuous length. The outer contour of the tubular structure 40 can be round or oral and the preferred shape is either square or rectangular.

Abstract: 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].