Abstract: The invention relates to a print head (10) for a 3D printer (1), comprising a feed section (11) having a feeder (12) for a starting material (21) that is variable in the viscosity thereof; a plasticizing zone (14) having a heater (15) and an outlet opening (16) for the liquid phase (22) of the starting material (21); and a conveying device (30) for conveying the starting material (21) from the feed section (11) to the plasticizing zone (14), wherein the conveying device (30) comprises a piston (31) that can be inserted into the feed section (11). The invention is characterized in that the piston (31) has a first piston portion (5) facing the plasticizing zone (14) and having a guide surface (9), through which the piston (31) is guided in a bore (7) of the print head (10).

Abstract: A method for simultaneously producing several injection-molded parts. A mold is provided comprising a plurality of molding plates fluidically connected to each other and which combine form a plurality of mold cavities defining the contour of a finished injection-molded product. A material such as a plastic material is injected via an injection nozzle into one of the mold cavities such that the material flows successively through the mold cavities from one mold cavity to an adjacent mold cavity.

Abstract: A molding system (100), comprising: a shooting-pot assembly (102; 202A; 202B); and a valve assembly (104; 204A; 204B) having an input port (106; 206A; 206B) being configured to input a melt, an output port (108; 208A; 208B) being configured to output the melt, and a transfer port (110; 210A; 210B) connected to the shooting-pot assembly (102; 202A; 202B).

Abstract: A plastification and injection unit in injection-molding machines for processing of polymer materials, for example rubber, has a plastification screw that is disposed so as to rotate in a screw cylinder, which simultaneously represents the injection piston. The screw cylinder is disposed in an injection cylinder, in an axially displaceable manner. The injection cylinder can be connected with the sprue channel of an injection-molding die by way of a nozzle, and the injection piston has a back-flow barrier. The screw is axially displaceable in the screw cylinder by means of a separate drive. The screw tip projects out of the screw cylinder and has a closure body having a sealing surface for contact with the face surface of the screw cylinder.

Abstract: A method and apparatus are provided for moulding an article by feeding molten plastics material into a metering cavity (16), feeding a predetermined quantity of the material from the metering cavity into a mould cavity via a transition passage (26) adjacent the mould cavity and urging the molten plastics material from the transition passage into the mould cavity with a working stroke of a packing piston (24), until the packing piston closes a port (28) defined between the transition passage and the mould cavity and a leading face (32) of the packing piston forms part of the peripheral wall of the mould. Less than ninety percent of the mould cavity is filled with the molten plastics material when the packing piston starts its working stroke and the packing piston starts its working stroke while molten plastics material is still being fed from the metering cavity.

Abstract: In a method of operating an injection molding machine of a type having an injection plunger for pushing melt from an injection space anteriorly of an injection plunger into an injection mold, a plasticizing screw of an extruder is continuously operated to continuously feed melt through a melt channel into the injection space. A passage through the melt channel is closed to allow backup of melt backwards into the extruder, and the injection plunger is moved forward to inject a shot amount from the injection space into the injection mold.

Abstract: A plasticizing and injecting device for a plastics injection molding machine includes an axially fixed and rotationally driven plasticizing screw, and an injection plunger movable forwards and backwards inside the plasticizing screw by a linear drive and including, at its front end, a non-return valve. An injection cylinder is provided anteriorly of the plasticizing cylinder. The non-return valve can be moved by the injection cylinder forwards and backwards inside the injection cylinder between a rear position at the beginning of the injection process and a front position after completion of the injection process. In addition, a melt chamber is formed between the front end of the plasticizing screw and the non-return valve, and forms, during the injection process and during the holding pressure phase, an annular gap between the injection plunger and the injection cylinder for receiving plastic melt as the plasticizing screw continues to rotate during injection.

Abstract: The present invention relates to an injection unit of a two-stage injection molding machine having an injection device and a meter device for providing plastic to the injection device. The injection motor of the injection device is secured to the base and does not move along with the injection linkage member so as to decrease the movement momentum and improve the injection response and acceleration capability. Additionally, the injection device can adopt a plurality of injection motors for meeting the injection capability requirement without employing high power injection motors. The length of the injection molding machines is relatively shortened, thus the problem of the prior arts is solved.

Abstract: A rubber injection molding device comprising: a mold having a molding cavity therein; an injecting machine including an injection cylinder having an injection chamber for storing a rubber therein, and an injection plunger for injecting the rubber from the injection chamber into the molding cavity by means of an advancement of the injection plunger; a feed machine having a feed cylinder with a feed aperture formed at a tip end thereof and connected with the injection chamber through a feed duct, and being adapted to feed into the injection chamber, through the feed duct the rubber in a mixed state, and a pushing assembly which pushes into the injection chamber the rubber that remains within the feed duct after a feed operation of the rubber by the feed machine. A manufacturing method of a rubber product by using the molding device is also disclosed.

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: Embodiments of the present invention relates to an injection moulding machine or injection unit and to an injection moulding method for injection moulding plastic materials (e.g., elastomeric materials), particularly according, to cold channel and hot channel techniques, comprising an extruder, a first piston/cylinder unit and a second piston/cylinder unit mounted in series thereto. The cylinder of the first piston/cylinder unit leads into the end of the second piston/cylinder unit located at a distance from an injection mould to be filled. According to an aspect of the invention, the elastomeric material is firstly led by means of the first piston/cylinder unit through the cylinder of the second piston/cylinder unit and into the injection mould, wherein the piston of the second piston/cylinder unit frees the flow path to the injection mould.

Abstract: A hot runner system includes a having a cavity. Melt is fed from a source of melt into the cavity, and a valve isolates melt in the cavity from melt in the source. A plunger within the cavity is driven forward to inject melt in the cavity into a mold cavity at high pressure without significantly increasing the pressure of melt in the source. The plunger optionally functions as both the plunger and the valve by opening and closing communication between the cavity and the manifold as it is rotated.

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: In an injection device 10 having a plunger 11 reciprocably inserted into a heating cylinder 16, in which a molten material M is injected by the plunger 11 via a nozzle 21, a sealing portion 13 set so that the molten material M is prevented from easily entering a gap A between the plunger 11 and an inner wall 32 of the heating cylinder 16 is provided on the portion of the plunger 11, on the side of the nozzle 21, and the portion of the sealing portion 13, on the side of the nozzle 21 is a core keeping portion 14 provided so that an annular portion 20 which is formed on a front portion of the plunger 11 and is connected to a storage portion 19 of the molten material M is formed between the core keeping portion 14 and the inner wall 32 of the heating cylinder 16.

Abstract: A discharge apparatus for a two-stage injection molding machine, includes a check shaft seat having a runner, and disposed between a feeding portion and an injection portion of the two-stage injection molding machine, for allowing a plastic material in the feeding portion to enter the injection portion via the runner; at least one check shaft disposed in the check shaft seat, and for opening and closing the runner via movement of the check shaft; at least one cover provided at a side of the check shaft seat, and having at least one discharge hole for discharging residues of the plastic material between the check shaft seat and the check shaft; and at least one adjustable unit for adjusting a discharge speed of the residues of the plastic material. The discharge hole and the adjustable unit can prevent locking of the check shaft and pollution from degraded residues of plastic material.

Abstract: A method for making foam products steps of preparing variety of foam materials with different colors, mixing the materials in a final tank, feeding the materials in a mold, heating the materials which are then foamed to form a product which is then removed from the mold and cooled. The method is proceeded by a device which includes first tanks for receiving the variety of foam materials, second tanks for being fed with pre-set amount of the variety of foam materials, and a final tank which has mixture of the variety of foam materials. The mixture is then sent to a mold to be heated and foamed.

Abstract: A device for expansion injection moulding, by which a polymer melt placed under pressure by a main pressure source can be injected from a storage chamber (4) into a mould cavity (3) by expansion of the polymer melt stored under pressure, the injection is optionally assisted by elastic deformation of the wall (8) of the storage chamber (4) and/or the wall (7) of a runner 6 leading to the storage chamber (4), the storage chamber (4) having an exit (5) which can be shut off, wherein the storage chamber (4) is arranged in a mould (1) which forms the mould cavity (3) and an additional pressure accumulator and/or an additional pressure source is (are) provided which is (are) capable of exerting additional pressure on the polymer melt during injection of the polymer melt into the mould cavity (3), in order to fill—preferably completely—the mould cavity (3).

Abstract: A vertical micro-injection machine includes a plasticizing unit, in which a feeding channel is provided and a screw or a plunger for transporting the molten material is provided in the feeding channel; an injection unit adapted to receive a metered amount of molten material from the plasticizing unit; an injection mold adapted to receive the metered amount of molten material from the injection unit; at least two thrust cylinders adapted to close the injection mold before injection and open the injection mold after injected parts solidified; and the injection unit includes an injection cylinder, the injection cylinder is connected with the feeding channel of the plasticizing unit, and a vertically reciprocating plunger is provided in the injection cylinder, which can expel air above the molten material in the injection cylinder by its upward advancement and then push the molten material into the injection mold.

Abstract: An injection unit for an injection molding machine includes a plasticizing unit in the form of an extruder, a plunger-type injection device, which can be connected to the injection molding machine by an injection nozzle. The plunger-type injection device defines an injection space. The extruder has a forward portion which is connected to the injection space by a melt through channel in which a shutoff valve is disposed. The extruder is operated continuously and includes one or more plasticizing screws, wherein the extruder is configured in such a way that the backup length can expand backwards into the extruder, when the shutoff valve is closed.

Abstract: An injection unit for injection molding machines includes an extruder as plasticizing unit and a plunger-type injection molding device that can be coupled to the injection molding machine by an injection nozzle. The plunger-type injection molding machine has an injection plunger, wherein the area in front of the injection plunger forms an injection space which is connected to a forward end of the extruder by a melt channel, with a shutoff valve disposed in the melt channel. The extruder can be continuously operated and has one or more plasticizing screws for plastification, wherein the extruder is so configured that a backup length is able to increase backwards into the extruder, when the shutoff valve is closed.

Abstract: An injection molding shooting pot 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 injection molding shooting pot includes a shooting pot piston having a proximal end and a distal end. A shooting pot piston extension is disposed at the distal end of the shooting pot piston, and is configured to dislodge a check valve moving element during a discharge cycle of the shooting pot piston.

Abstract: A two-stage injection molding machine having a pressure sensor device is proposed. The two-stage injection molding machine includes an injection part having an injection cylinder, a driving unit, and an injection rod installed in the injection cylinder; a metering part for feeding plastic material to the injection cylinder of the injection part; and a loadcell installed between the injection rod and the driving unit, wherein pressures in the injection cylinder during the feed metering, injection, and packing processes are detected via the loadcell and the pressure sensor rod. As a result, an accurate pressure feedback control is implemented to achieve high precision injection molding quality. And with the two-stage injection molding machine having such a simple structural design, occurrence of signal distortion and delayed response is prevented.

Abstract: A metering device for an injection molding unit includes a base body having an antechamber in fluid communication with a feed channel for introduction of plastic material, and a metering chamber in fluid communication with a injection channel. The antechamber and the metering chamber are connectable with one another by a closeable passageway. Movably arranged in the base body between the antechamber and the metering chamber is a displacement member in the form of a piston to separate the antechamber and the metering chamber. The piston has a first end face which demarcates the antechamber and a second end face which demarcates the metering chamber, with the first end face defining an effective area which is smaller than an effective area of the second end face.

Abstract: An apparatus for filtering viscous material, in particular thermoplastic synthetic plastic material, comprises a screw (24), which presses the material to be cleaned from an upstream conduit (3) of a supply housing (2) towards a band-shaped screen (4). The screen (4) is abutted on its downstream side by a perforated plate (6) against the pressure of the supplied material. The band-shaped screen (4) can be displaced for replacement of a soiled band section by a fresh band section. For facilitating this displacement a device is provided, which comprises a closure means (30) that is disposed on the upstream side of the screen (4), by which closure means the upstream conduit (3) for the material to be filtered can be closed at least substantially. On the upstream side of this closure means (30) a storage space (36) for material to be cleaned is connected to the upstream conduit (3).

Abstract: An injection unit for an injection molding machine includes an injection device in the form of a plunger/screw, which is driven axially and rotationally in a housing, and a device intended for mixing and metering plastic melt and including an inlet for introduction of an additive. A spacer element is disposed between a backflow prevention assembly of the screw and the plunger, with the spacer element having a length, which corresponds at least to the stroke of the injection device. The spacer element has a first flow channel for establishing in each position a fluidic connection with a second flow channel which initially extends radially in an outward direction and then parallel to the movement and guide area of the plunger to an area between a nozzle and the plunger. The second flow channel extends through the mixing and metering device arranged adjacent to a movement and guide area of the plunger.

Abstract: Apparatus for manufacturing a multicolor slide fastener includes an upper die 110, a lower die 120, and a plurality of unit fastening teeth-forming slots 101 formed in a lengthwise direction. Molding material-injecting passages and a plurality of sprue holes 102 are provided for injecting the molding materials S into the slots 101. Inclined passages 201 and 202 are connected to the molding material injecting passages respectively, for carrying the molding materials S from a raw material source. Heaters 240 and heat sensors 241 heat the passages 201 and 202. Pressing means 300 press the molding materials S into the inclined passages 201 and 202. Valves 400 control injection of the molding materials S into the sprue holes 102 of the upper die 110.

Abstract: An injection molding compounder includes an extruder with an extruder housing and at least one extruder screw rotatably arranged in the housing, for production of melt, and an injection device is fluidly connectable to the outlet of the extruder. An accumulator for temporarily storing melt is connected to the extruder housing in conveying direction of the extruder at a location upstream of the outlet in an area of the extruder screw so that melt produced in the extruder can be stored in the accumulator.

Abstract: A mold valve assembly includes an air injection system that communicates with the mold valve assembly. The air source provides air into the mold assembly to pressurize a space between the cured molded article and an inner surface of the mold cavity to promote separation of the cured molded article from the mold assembly.

Abstract: A mold valve assembly includes a mold valve chamber having an output port and an injection chamber in communication with the mold valve chamber. A first actuator drives an injection piston within the injection chamber to drive mixture material from an inlet port into the mold valve chamber. A second actuator drives a mold valve piston along the mold valve axis within the mold valve chamber to drive mixture material through an outlet and into a mold cavity of a mold assembly. The mold valve piston closely fits within the mold valve chamber to scrape along an end segment of the injection piston to clean any mixture material remnants therefrom such that remnants within the mold valve chamber are minimized and the necessity of flushing between injection cycles is substantially eliminated.

Abstract: The invention relates to an injector unit and a method for the control of the injection process into the cavities of injection moulding tools. The novel solution permits the injection of thin-walled injection moulding pieces (76, 77), with both electrically- and hydraulically-driven injector screws. One of the most important features thereof is the active selection of the opening time of the locking system at an optimal pressure in the compression chamber, preferably in the region of the upper half of the compression. The volumetric transfer flow is thus significantly improved in thin-walled injection moulding pieces (76, 77). Above all the melting pressure in the tool, the flow speed and the useful flow path in the cavities are increased.

Abstract: The retraction of the screw is controlled on the basis of the pressure deviation between the set resin pressure and the detected resin pressure. Furthermore, the screw is caused to rotate at a set speed. Moreover, when the deviation between the metering completion position and the current screw retraction position drops to a value that is equal to or less than a set value, control of the retraction of the screw based on the pressure deviation is stopped, and the control is switched to positioning control based on the positional deviation. Furthermore, a screw rotational speed command in which the pressure deviation component between the set resin pressure and the current resin pressure is corrected from the screw rotational speed component that is decelerated in proportion to the positional deviation is determined and output.

Abstract: A screw is rotated at a set speed and retreated by performing back pressure control for keeping a resin pressure at a set pressure. When the retreat position of the screw reaches a change point set nearby a set metering completion position, the back pressure control for keeping the resin pressure at a set resin pressure is stopped. A command for positioning the screw at a metering completion position is output to position the screw at the metering completion position. At the same time, when a screw position reaches the change point, the screw is reversed by a set value at a set speed.

Abstract: The present invention provides blowing agent introduction systems and methods for introducing blowing agent into polymeric foam processing systems. The methods may involve introducing one or more doses of blowing agent into polymeric material in an extruder during a plastication period of a molding cycle. Prior to introduction, a dose is confined in an accumulator which, for example, has a volume defined between an inlet valve and an outlet valve. A control system may receive inputs related to system parameters (e.g., pressure of polymeric material in extruder, axial position of screw in barrel, whether screw is rotating, and the like) and based on the inputs coordinates operation of the valves to confine and introduce the blowing agent dose(s). The introduction systems may be used in discontinuous plasticating processes, such as injection molding and blow molding, and can be particularly useful in processes that use precise quantities of blowing agent.

Abstract: An object of the present invention is to provide an injection apparatus capable of enhancing efficiency, reducing size, and enhancing durability of an injection member. The injection apparatus includes an injection member disposed reciprocatably in a cylinder member, a linear motor device (49) for advancing the injection member when operated, a metering member disposed rotatably in the cylinder member, and metering drive means for rotating the metering member. In this case, in an injection step, the linear motor device (49), when operated, can directly advance the injection member to thereby perform injection; therefore, occurrence of energy loss can be prevented. As a result, the efficiency of the injection apparatus (43) can be enhanced.

Abstract: A resin transfer molding (RTM) process is disclosed for rapidly filling a fibrous preform and/or a rigid, porous body with high viscosity resin or pitch. The process is suitable for impregnated multiple porous bodies stacked in a single mold. The process uses a fibrous preform or rigid porous body which is placed into a mold matching the desired part geometry. A resin is injected into the mold at temperature and pressure. After cooling, the infiltrated component is removed from the mold. The mold is constructed from two halves fitted to form at least one mold cavity. A gate fitted with a nozzle is set into one of the mold halves, and a valve admits resin or pitch into the gate area. Venting or vacuum can be applied to the mold. The mold is held in a hydraulic press and an extruder, optionally fitted with an accumulator, supplies molten resin or pitch to the mold.

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 moulding machine for producing small plastic components with a drive unit (6, 84), a plasticizing device (4, 42) and a hot channel nozzle (1) having a collection chamber (10) for the molten plastic. An injection ram (35) projects into the hot channel nozzle (1) and can push the collected plastic out. In an embodiment, the plasticizing device (4, 42) and the drive unit (6, 84) are secured to a movable bearing housing (85) and can move the injection ram (35).

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 injection assembly for an injection molding machine, with a continuously operating plasticizing unit, includes a piston-type injection unit and an arrangement for intermediate storage and discharge of melt. Several melt reservoirs with melt inlet openings are provided between the plasticizing unit and the piston-type injection unit. Melt lines that connect the melt reservoirs with each other and with the plasticizing unit extend to the melt inlet openings. The melt reservoirs include actuatable work pistons for discharging the melt, wherein the work pistons can open and close the melt inlet openings in the melt reservoirs to divert the melt flow. The disclosed injection unit increases the total volume of bufferable melt and allows individual and separate adjustment of the reservoir volumes and the discharge velocity of the individual melt reservoirs. In addition, switching valves can be eliminated since the melt flow is switched by the work pistons.

Abstract: A system for injection moulding of large plastics components in a single shot comprises an extruder and an accumulator fed from the extruder The accumulator leads into the mould (14) via a mould valve (12) opive, when closed, to close the mould cavity substantially at the mould surface and also to close an outlet (20a) from the accumulator. The valve passage of the mould valve is of relatively large cross-section, typically several centimetres or more which facilitates injection at relatively low pressures and also facilitates passage of stones and other particulate matter which may be present if the extrudate is composed of post-consumer recycled plastics.

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: The method includes the steps of a tape arranging step for arranging a support tape of a slide fastener on a mold having a capacity having a plurality of unit fastening element molding material grooves for molding a plurality of unit fastening elements, a molding material heating and discharge step for separating a molding material of more than two colors from a source material supply unit by the colors by a molding material injection means and then heating and discharging the same, a moving step for grouping external molding material flow paths from the molding material supply unit to an injection port of the mold into more than two groups and then moving different colors molding material by the colors, and an injection step for injecting the molding material into the unit fastening element molding material groove through a plurality of inject-on ports formed in the mold.

Abstract: An apparatus to actuate an injection element (1) for injecting a defined quantity of plasticized plastic or the like into an injection molding tool. The injection element (1) is designed as a piston or as a screw and is guided in a guide (2) and moved by an actuation element. The actuation element (3) has a tappet (4), which is guided on a crank plate (5), the crank plate (5) being turned with positional accuracy by a controlled or regulated servomotor (6). The invention provides that, for the return stroke of the injection element (1), a second tappet (7) is present, which is actuated by a second crank plate (8).

Abstract: A method for injecting plastic material or another injectable material into an injection molding tool comprises the following steps: plasticizing the plastic or other injectable material in a plasticizing apparatus (2); transporting the plasticized plastic or the plasticized other injectable material into a dosing apparatus (3), which has a fluidic connection (4) to the plasticizer apparatus (2), and specifically in essentially precisely the quantity that is to be introduced into the injection molding tool (1); transporting the plasticized plastic or the plasticized other injectable material, essentially in that quantity which is to be introduced into the injection molding tool (1), from the metering apparatus (3) into an injection apparatus (5), via a fluidic connection (6), while at the same time preventing the plastic or other injectable material from backflowing from the metering apparatus (3) into the plasticizing apparatus (2); injecting the entire quantity of plastic or the entire quantity of another i

Abstract: A system for providing a desired quantity of a mold material into a mold. The system includes an accumulation system and a metering and delivery system. The accumulation system is a temporary reservoir which accepts and stores mold material and then provides the mold material to the metering and deliver system under pressure on demand The accumulation system is exemplified by a cylinder and a pneumatically actuated piston within the cylinder which is capable of selectively withdrawing and advancing so as to accept and then supply mold material under pressure. The metering and delivery system is exemplified by a metering cylinder and a pneumatically actuated metering piston within the cylinder that has a stroke length that defines a volume that substantially corresponds to the volume of mold material that is delivered to the mold. Adjustments to the stroke length of the metering piston may be made in order to fine tune the quantity of mold material that is placed into the mold.

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: The invention is directed to a bi-directional check ring for a two-stage injection unit. More specifically, a close fitting ring is inserted behind the plunger head of the melt accumulator so that normal running clearances between the plunger and barrel bore can be used. The outer diameter of this check ring has a very close fit with the inner diameter the injection barrel, but is not rigidly connected to the plunger. Accordingly, the plunger is free to “floats” while injection and plastication/filling take place. The open volume between the ring and plunger is small, but sufficient to permit the ring to “float” very close to the barrel inner diameter, without being influenced by the alignment of the plunger and injection drive motor.

Abstract: A vertical molding machine vertically provided with a pre-plastication injection unit where an injection unit and a plastication unit are mounted side by side. The tips of these units are linked by a connecting pipe to transfer resin plasticated by the plastication unit to the injection unit therethrough. The injection unit and the plastication unit are individually supported by respective pairs of supports standing upright above a clamping device. The injection unit has an arm member on either side thereof and a spring member is provided on the top of the arm member. The plastication unit is held on the arm member through the spring member, where the supports for the plastication unit are inserted through the arm member and the spring member.

Abstract: In an injection molding machine for thermoplastic resin, a mold clamping hydraulic circuit is constituted as a hydraulic circuit which can be optionally set to a pressure-free or substantially pressure-free state upon completion of closure of a mold mounted to a clamping unit. A movable mold of the clamping unit can be retracted with a low injection pressure by injecting the molten resin via an injection unit. A nozzle port opening to a space of a mold cavity is closed simultaneously with completion of the charge of predetermined amount of resin, and a mold clamping force at a high pressure is generated on the forward side of the mold clamping unit, thereby producing mold clamping at a predetermined position. Since the mold is in a pressure-free or substantially pressure-free state, the injection pressure may also be low.

Abstract: A method and apparatus are provided for moulding an article by feeding molten plastics material into a metering cavity (16), feeding a predetermined quantity of the material from the metering cavity into a mould cavity via a transition passage (26) adjacent the mould cavity and urging the molten plastics material from the transition passage into the mould cavity with a working stroke of a packing piston (24), until the packing piston closes a port (28) defined between the transition passage and the mould cavity and a leading face (32) of the packing piston forms part of the peripheral wall of the mould. Less than ninety percent of the mould cavity is filled with the molten plastics material when the packing piston starts its working stroke and the packing piston starts its working stroke while molten plastics material is still being fed from the metering cavity.