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: Molding apparatus for rapid transfer of molten resin or pitch in an infiltration molding process. The apparatus includes e.g. an extruder (4) for melting and conveying a resin or pitch and a mold (10) arranged so that resin or pitch is conveyed to a mold insert cavity (19) within the mold. The mold insert contains an internal protrusion such as a locating ring (25) for positioning a porous body (1, 18) within the mold insert cavity in a position that brings about unidirectional flow of the molten resin or pitch through the porous body. Also, rapid resin or pitch infiltration molding process that includes injecting a high melting point, high viscosity, molten resin or pitch into the mold to effect a unidirectional impregnation of a heated preform via a pressure gradient in the mold.

Abstract: A gas extraction structure (40) is used for a mold apparatus (100). The gas extraction structure connects with a mold cavity (300). The mold cavity includes an end portion of a plastic injection path (210). The gas extraction structure includes a gas vent (490), a gas vent pin (49), and a support structure (40). The gas vent communicates with the end portion of the plastic injection path. The gas vent pin received in the gas vent. The support structure is fixed with the gas vent pin and brings the gas vent pin to move in the gas vent.

Abstract: The invention relates to a mould for encapsulating electronic components mounted on a carrier, comprising: at least two mould parts displaceable relative to each other, at least one of which is provided with a recess, and feed means for encapsulating material, wherein at least one of the mould parts is provided with a runner which connects on one side to a wall of a mould part co-defining a mould cavity and connects on the other side to a side of the mould part remote from the mould cavity. The invention also relates to an encapsulating device of which such a mould forms parts, and to a method for encapsulating electronic components mounted on a carrier.

Abstract: A system for molding dispensing valves includes first and second mold sections, at least one of which is movable with respect to the other between a closed position in which the mold sections form a plurality of dispensing valve mold cavities, and an open position in which the mold sections are spaced from each other and the mold cavities are open along a mold parting line. A transfer mechanism is movable between the first and second mold sections in the open positions of the mold sections for receiving molded valves from the cavities and transferring the valves from between the mold sections.

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: The invention relates to a device for producing plastic articles by forming them in an inert atmosphere, the device comprising a hopper, a feed screw and means for forming the polymer melt. The device for injecting inert gas comprises a gas feed pipe, a gas injection surface near the wall of the hopper and a homogenization chamber fitted between the wall of the hopper and the gas feed pipe. That end of the gas feed pipe which is directed towards the injection surface is closed and has at least one radial opening O allowing the gas to be ejected at right angles to its direction of flow in the pipe.

Abstract: A molding die apparatus and a method thereof are provided, which ensures for air and gas (or fluid) present in a resin filling space to be exhausted so as to be able to fill molten resin into the cavity smoothly and uniformly thereby enabling production of a high quality molded resin product suitable as an optical disc substrate or the like having optimum optical properties required therefor. The molding die apparatus for obtaining the molded product by injecting the molten resin into a cavity that is formed between dies includes a vacuum apparatus which is disposed in proximity to the cavity, the vacuum apparatus including a vacuum tank, an exhaustion channel and a vacuum valve which controls open and close of a channel between the vacuum tank and the exhaustion channel, and the cavity is exhausted efficiently and rapidly by the vacuum apparatus.

Abstract: An injection molding apparatus (10, 110) for molding an annular thermoplastic element, such as an annular closure element (E) with no more than a single weldline in the annular extent of the thermoplastic element. The thermoplastic element is molded in an annular mold cavity (12, 112), and moldable thermoplastic material (M) is introduced into the mold cavity from a coaxially-aligned annular flow path (18, 118) that is defined between a sliding sleeve (24, 124) and an annular member (22, 122). The sliding sleeve surrounds and is slideable with respect to a fixed pin (26, 126) and is slideable between a first, or forward, position, where no thermoplastic material can flow into the mold cavity, and a second, or rearward, position, where thermoplastic material can flow into the mold cavity.

Abstract: A machine for processing individual food items comprises a mold plate having multiple longitudinally spaced transverse rows of cavities. The mold plate slides such that the rows of cavities sequentially communicate with a fill slot in a fill plate. Bulk food material fills the cavities and displaces air from them into a breather plate. The breather plate has one or more longitudinal grooves in a working surface. The fill plate has one or more longitudinal grooves in a working surface that communicate with the atmosphere. One or more vent holes in the mold plate communicate with the breather plate and fill plate grooves for all positions of the mold plate at which food material is filling a row of cavities. No air is trapped in the breather plate, and there is no buildup of air pressure that could create a friction force between the mold plate and the fill plate.

Abstract: In a conventionally used injection molding apparatus, undried resin pellet is put in a drier of a predetermined temperature and water and gas in the undried resin pellet is completely removed, and the dried pellet deprived of water and gas is thrown into the injection molding apparatus. It is therefore necessary to carefully control quality of water and gas of pellet before pellet is thrown into the injection molding apparatus. In injection molding of undried resin pellet, evaluate injected resin, control operation conditions such as the feeding amount of pellet and the decompression degree, and determine the best operation conditions and the best accumulation amount wherein excellent articles are obtained. The accumulation amount of pellet fed in an injection molding chamber is detected, and feeding to the injection molding chamber is controlled upon the detection information.

Abstract: A first injection mechanism of an apparatus for molding articles injects coating material into a cavity defined in a clamped mold, thereby forming a predetermined coating on the inner surface of the cavity. After the coating material is injected into the cavity, a decompression mechanism lowers the pressure in the cavity through at least one vent. After the coating is formed on the inner surface of the cavity, a second injection mechanism injects molding material into the cavity. When the pressure in the cavity is being lowered, an opening-closing mechanism opens the vent. Before or during the injection of the molding material, the opening-closing mechanism closes the vent.

Abstract: In the field of vacuum-assist-resin-transfer-mold (VARTM) processing, a new system is provided to lower production times and to create a high permeability mold cavity with reduced directionality to yield an optimum flow-front. The system comprises the use of a high permeability layer to evacuate air from the mold cavity and may include a reusable port-runner device for introduction of resin into the fiber mat. In the preferred embodiment, the high permeability layer is a “felt-like” material constructed of synthetic fibers, and the reusable port device is a flat, modular unit. In another embodiment, the high permeability layer is a fluid-impervious material with sporadic protrusions, and the reusable port-runner device is a flexible, silicone unit. Other embodiments are comprised of any combination thereof. Each embodiment is designed to minimize set-up times and to create a mold cavity with a low resistance to fluid flow through the application of pressure differentials.

Abstract: A soft plastic fishing lure or other product may be made to float by incorporating air bubbles therein by molds that draw air from inside the molds in which the lures or products are cast.

Abstract: Method and apparatus for molding an IOL comprising first and second mold halves each having an optic forming surface and haptic forming surfaces which together define a mold cavity in the shape of the IOL to be molded therein when the mold halves are assembled together. An injection port is formed and connects to one of said haptic forming surfaces or the optic forming surface wherethrough a polymerizable material is injected into the mold cavity. A venting port is formed and connects to another haptic wherethrough air escapes from the mold cavity as the polymerizable material is injected through the injection port.

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

Abstract: A method of manufacturing a molded article from a settable mixture includes the steps of in-taking a plurality of components into a plurality of separate material discharge containers sized relative to each other to provide the required mix ratio of the settable mixture. The components contained in the material discharge containers are discharged to a mold tool through a mixing head that receives each of the components separately and thoroughly mixes them into the settable mixture. The settable mixture flows from the mixing head to fill the mold tool. The mold tool rotates about an axis during the filling step to evacuate air from the mold tool. Pressure of the settable mixture is monitored during the filling step and rate of discharge of the settable component is varied in response to changes in pressure of the settable mixture.

Abstract: In an injection mold comprising a cavity and a gate for feeding a molding material into the cavity, the molding material fed from the gate into the cavity is divided into two streams that flow through the cavity and then meet at a confluent point so that the molding material portions are joined together along a joint plane. Two air vent gates are spaced apart from the confluent point so as to provide a larger area of the joint plane. Articles having a good outer appearance and improved strength at the material joint can be consistently manufactured to a high precision.

Abstract: An injection-molding machine cooling tube, which cools molded plastic parts, includes a porous cooling tube having an outer surface and an inner surface. Preferably, the porous cooling tube has a porosity in the range of 3-20 microns. A cooling fluid passageway is preferably disposed adjacent the porous cooling tube outer surface and is configured to carry a cooling fluid to extract heat from the porous cooling tube. Fluid flow structure, preferably a vacuum, is configured to cause a molded plastic part inside the porous cooling tube to expand into contact with at least a portion of the inner surface of the porous cooling tube.

Abstract: A method and apparatus for removing melt from a stagnation zone in a melt conduit extending from a melt source to a mold cavity is provided. The stagnation zone may be created by the presence of a valve pin in the melt conduit for controlling melt flow therethrough. The apparatus includes a stagnation zone cleaner that is moveable through the stagnation zone for urging melt out of the stagnation zone.

Abstract: A vale assembly for a RIM system includes a body which defines a passage, a support structure within the passage, a poppet, and a detachable member which retains the poppet to the support structure. The valve assembly threads into a vent within a mold to provide a communication path for expanded material within the mold cavity. In operation, when a flow through the passage is below a predetermined force the detachable member is retained upon the stem and the valve remains open to provide venting of the mold cavity. Once the mixture expands into a more solid material and expands into the vent and valve assembly, the material flow provides a greater force against the poppet. Eventually, when a predetermined material flow generates a force upon the poppet greater than the predetermined force, the detachable member is detached from the stem and the poppet is pulled from the support structure.

Abstract: Solid rollers of a urethane material are formed in closed mold formed by a tube and two end plugs spaced by a shaft, the latter becoming the shaft for the roller. The closed mold avoids rough grinding to a cylindrical shape, as well as avoiding the resulting waste of material and introduction of defects that arise from rough grinding. The formation of bubbles during injection of the urethane material is avoided by filling the closed mold with carbon dioxide gas prior to injection. The formation of gate marks in the urethane material is avoided by repositioning the end caps after injection to separate the injection gate from the cylindrical cavity. The need to trim the ends of the roller is avoided by providing an annular cavity between the top end cap and the tube that receives excess urethane material to be drawn into the cylindrical cavity as the urethane shrinks during curing.

Abstract: The invention concerns a method and a moulding device in which an inner liner of a fluoroplastic foil in a vacuum infusion moulding or vacuum assisted pressure process for the manufacture of fibre reinforced composite products in Resin Transfer Moulding (RTM) process. By the method and the moulding device, a simple closed moulding technique is provided, which is cost efficient, as the backing foil is reusable.

Abstract: The invention relates to a device for producing plastic articles by forming them in an inert atmosphere, the device comprising a hopper, a feed screw and means for forming the polymer melt. The device for injecting inert gas comprises a gas feed pipe, a gas injection surface near the wall of the hopper and a homogenization chamber fitted between the wall of the hopper and the gas feed pipe. That end of the gas feed pipe which is directed towards the injection surface is closed and has at least one radial opening o allowing the gas to be ejected at right angles to its direction of flow in the pipe.

Abstract: The molding device comprises a lower mold unit and an upper mold unit. When the upper mold unit approaches the lower mold unit, a molding cavity is defined between the lower and upper mold units. The lower mold unit has a storing chamber that is. communicated with the molding cavity. The lower mold unit comprises a pressure-decreasing mechanism and a pushing mechanism. A molten material is stored in the storing chamber. When the molding cavity is formed between the lower mold unit and the upper mold unit, the pressure-decreasing mechanism decreases pressure in the molding cavity. Afterwards, in sync with the operation that the upper mold unit pushing down a lower mold-holding member of the lower mold unit, an injection rod of the pushing mechanism pushes out the molten material in the storing chamber to the molding cavity. As a result, the efficiency of the molding operation is improved.

Abstract: An frame opening cover plate for an injection mold system having an upper stationary portion and a lower movable portion. The upper portion has a support member and a cavity core, while the lower portion has a frame having side walls, a bottom and a support member defining an interior housing with openings on each end. An ejector assembly is positioned within the housing and is movable to eject newly molded products when a molded product has been formed. The openings in the frame can result in the collection of dust, moisture and other foreign materials inside the housing and the possible damage to the mold or ejector assembly, so a frame cover plate is provided. A cover plate covers each opening during operation of the system and when the system is inactive or stored.

Abstract: A method and apparatus for shape forming of degradable polymers under the protection of an inactive gas is disclosed to use an injection-molding machine to mold a degradable polymer into final products, and to use an inactive gas to form an air shield that isolates the supplied degradable polymer from air during injection molding.

Abstract: In an injection mold comprising a cavity and a gate for feeding a molding material into the cavity, the molding material fed from the gate into the cavity is divided into two streams that flow through the cavity and then meet at a confluent point so that the molding material portions are joined together along a joint plane. Two air vent gates are spaced apart from the confluent point so as to provide a larger area of the joint plane. Articles having a good outer appearance and improved strength at the material joint can be consistently manufactured to a high precision.

Abstract: Apparatus and method for cooking snack food pieces features a drum-type fryer which transports individual, die-cut piece preforms through hot oil contained within a cooking tank defined between the periphery of the drum and a housing in which the drum is contained. Vacuum transfer and feed rollers transfer the individual piece preforms from a die-cutting roller assembly onto the drum for cooking, and a similar roller transfers the cooked snack food pieces from the drum to a take-away conveyor for subsequent, downstream processing. The pieces are retained by suction against molding surfaces of frying mold elements distributed over the periphery of the frying drum.

Abstract: A casing 2 constitutes a connector casing E required to have a sealing property, and the cover 2 is constituted by a cover main body 10 provided with, in its own part, a large vent hole H0 passing through the connector casing E in an inward and outward direction and having a predetermined inner diameter size; a permeable sheet S which has a property to permit permeation of a gas and to prevent permeation of a liquid and a solid, and is integrally joined to an outside peripheral part of the large vent hole H0 so as to cover the large vent hole H0 from its outside; and a cover member C which is disposed outside the permeable sheet S to cover the permeable sheet from its outside and a ring-shaped protrusion 22 of which is hermetically joined to the casing main body 10, and the cover member C1 is provided with a small vent hole H1 in its own inward and outward direction, which has an inner diameter smaller than the large vent hole H0 and connects the large vent hole H0 and the air through the permeable sheet S.

Abstract: A modular molding system having: an upper frame assembly configured for receiving a cavity module therein; a lower frame assembly configured for receiving a core module therein, the lower frame assembly including a two-stage master ejector system; a cavity module positioned within the upper frame assembly; and a core module positioned within the lower frame assembly, the core module including a two-stage ejector system having a plurality of ejection elements associated therewith; wherein the core and cavity modules together define a molding cavity for molding a workpiece therein, and wherein the master ejector system is operable to drive the ejection elements of the core module.

Abstract: A molten material supply unit includes a heating cylinder. The heating cylinder may receive and heat the material in a substantially vacuum condition. A molding apparatus may include a pressurizing and charging unit in addition to the molten material supply unit. The pressurizing and charging unit is adapted to receive the melted material from the molten material supply unit and to charge the melted material into a die under pressure.

Abstract: A method and apparatus for vacuum assisted venting of an injection mold. The apparatus includes a main body structured to be mounted around an outer circumference of the injection mold and configured to facilitate application of a vacuum pressure therein. The method and apparatus are particularly directed towards preventing the accumulation of residual material inside an injection mold and reducing the frequency of disassembly and cleaning required for the injection mold.

Abstract: So that a method for the surface coating of an interior fitting for vehicles with a lacquer or resin layer, in which the interior fitting to be coated is inserted into a cavity of a molding tool, the inner wall of which is at a defined distance from the interior fitting in the region of the interior fitting surface to be coated and thereby forms a clearance extending over the entire surface to be coated and having a substantially constant thickness, and in which a liquid surface coating material is introduced into the clearance and is cured there, can be developed in such a way that the quality of the surface coating is improved as far as possible without additional after-working, it is proposed that the surface coating material have at least two components which are mixed with one another in a mixing and feeding assembly immediately before the filling of the clearance and are fed to the clearance, and that, after the clearance has been filled, the molding tool be separated from the mixing and feeding assembl

Abstract: A method of resin molding for molding regular products and a resin molding machine for the same. In the method of the present invention, release film, which is capable of easily peeling off from molding dies and resin, is provided on faces of molding dies. A member to be molded by the molding dies 15 is clamped together with the release film. An inner face of a pot of the molding die is covered with the release film. A resin tablet is supplied into the pot.

Abstract: An improved vent pin for a golf ball injection mold is characterized by a non-circular configuration so that a non-circular dimple can be formed at one or both poles of the golf ball. The vent pin is coaxially arranged within a passage in the injection mold which is aligned with a radius of the ball which passes through one of the poles thereof. The pin is operable between a normal position where the end of the pin closes the passage lower end and a retracted position where the pin end is withdrawn into the passage so that air from a cavity of the mold where the cover layer of the ball is formed can be vented during delivery of thermoplastic material to the cavity to form the golf ball cover.

Abstract: In a mold device for injection molding of synthetic resin having a cavity surface alternately heated and cooled and a bottoming structure for producing a product having a bored portion like a window, a bottoming portion for the production of a product having a bored portion is provided on a parting surface of the mold and a vacant space is provided in the bottoming portion. Thus, the contact area of the bottoming portion is reduced and a contact pressure of the bottoming portion and thermal strain due to a temperature difference between the cavity side mold and core side mold are reduced, so that it is possible to prevent occurrence of crack in a portion located immediately outside the window of the product.

Abstract: A mold plate assembly for a patty forming apparatus includes a mold plate having patty forming cavities and a breather plate arranged facing the mold plate. A fill slot is arranged facing the mold cavities, on a side opposite the breather plate, to fill food product into said mold cavity when the mold plate is in a filling position. The breather plate includes first breather holes at a remote position from the inlet slot to discharge air to ensure an even and uniform filling of the food product into the cavity, and second breather holes located close to the fill slot to relieve filling pressure at that location to avoid the formation of a ridge on the finished formed food patty.

Abstract: A molding die apparatus and a method thereof are provided, which ensures for air and gas (or fluid) present in a resin filling space to be exhausted so as to be able to fill molten resin into the cavity smoothly and uniformly thereby enabling production of a high quality molded resin product suitable as an optical disc substrate or the like having optimum optical properties required therefor. The molding die apparatus for obtaining the molded product by injecting the molten resin into a cavity that is formed between dies includes a vacuum apparatus which is disposed in proximity to the cavity, the vacuum apparatus including a vacuum tank, an exhaustion channel and a vacuum valve which controls open and close of a channel between the vacuum tank and the exhaustion channel, and the cavity is exhausted efficiently and rapidly by the vacuum apparatus.

Abstract: A vent, system and method for controlling flow of fluid into and out of a mold cavity. The vent has a plurality of passages that each have narrow oblong slot-shaped openings in the mold cavity and which each expand in size in a direction leading away from its opening. The vent preferably is an insert that comprises a grate with at least a plurality of vent slots. The grate preferably is formed of two halves with fingers that interleave to form the slots when assembled. The grate preferably is discharge machined from disc-shaped blanks cut from elongate stock made a material that preferably is non-porous and smooth. The grate can be mounted in a pocket in the mold cavity or carried by a movable pin. A system uses valving and a source of fluid and, if needed, a source of vacuum to help facilitate venting by drawing atmosphere out of the cavity during molding. The system can also be used to introduce fluid through a vent such as for foaming moldable material in the cavity.

Abstract: A system for molding a tissue or substitute tissue product in a mold having an exterior surface, and an interior surface, wherein at least one portion of the interior surface is porous and whose pores are in continuous communication with the exterior surface, and wherein said mold can be fabricated using solid free-form fabrication techniques is disclosed.

Abstract: Disclosed is a gas injection mold structure for use in the field of gas auxiliary injection molding, comprising a male mold and a gas injection device. The gas injection device includes a head and a cylindrical body extending from the head. The male mold is formed with a cylindrical cell. The cylindrical body has an outer periphery and the cylindrical cell has an inner wall being formed with matching outer and internal threads, respectively, such that the gas injection device is removably threaded into and affixed to the cylindrical cell by means of the cylindrical body. The cylindrical body is formed with a plurality of vertical grooves along an entire length of sides thereof.

Abstract: A plastic molding for use in an optical device, a method of producing the molding by injection molding, and an apparatus for practicing the method are disclosed. Only a part of a molding expected to sink is surely caused to sink while, e.g., a mirror surface is surely transferred to a desired part of the molding.

Abstract: An optical disc molding apparatus is able to mold an optical disc in which the occurrence of swollen portions of trumpet shape on the upper and lower surfaces of on the outer peripheral portion of a disc base may be minimized and in which a burr may be prevented from being produced on the outer peripheral portion of the disc base. In the optical disc molding apparatus having a ring (6) for molding an outer diameter portion of a disc base and holding a stamper (5) for transfer a signal pit, a holding surface of the ring (6) for holding the stamper (5) is formed as the concave and convex surfaces comprising a plurality of concentric land portions (21) and a plurality of concentric groove portions (22). The outer peripheral surface of the stamper (5) is held by each land portion (21) with a pressure.

Abstract: A plastic molding for use in an optical device, a method of producing the molding by injection molding, and an apparatus for practicing the method are disclosed. Only a part of a molding expected to sink is surely caused to sink while, e.g., a mirror surface is surely transferred to a desired part of the molding.

Abstract: A plastic molding for use in an optical device, a method of producing the molding by injection molding, and an apparatus for practicing the method are disclosed. Only a part of a molding expected to sink is surely caused to sink while, e.g., a mirror surface is surely transferred to a desired part of the molding.

Abstract: A mold for compression molding a resin article, which mold consists of male and female molds, wherein, at the time of complete mold closing, the length L in a mold closing direction of a mated part formed between the outermost wall of said male mold and the innermost wall of said female mold satisfies the equation: (t1−t0+10)mm≧L≧(t1−t0)mm wherein t1 is a distance (mm) between the male and female molds when the resin melt first reaches the mating outermost edge of the male mold, and t0 is a distance (mm) in the mold closing direction between the same points on the male and female molds as those used for measuring t1 when the mold closing is complete, and the horizontal distance of a mating gap between the outermost wall surface of said male mold and the innermost wall surface of said female mold is from 0.02 to 0.1 mm, with which mold, squeeze-out of a resin melt during molding is prevented.

Abstract: A multi-chamber vacuum encapsulation system for encapsulation of semiconductor chip packages. The encapsulation system includes a dispense chamber, an inlet chamber mounted adjacent an inlet end of the dispense chamber, and an outlet chamber mounted adjacent an outlet end of the dispense chamber. The dispense chamber includes a material dispensing head for dispensing encapsulant material about the peripheral edges of chip packages under at least partial vacuum of the dispense chamber. A transport mechanism is provided in the dispense chamber for moving the chip packages between the inlet and outlet ends of the chamber. During the encapsulation process, the dispense chamber remains evacuated at all times while the smaller inlet and outlet chambers are evacuated and vented in a controlled manner to allow transfer of chip packages to and from the dispense chamber without venting of the dispense chamber to atmosphere.

Abstract: A vent tube assembly is disclosed for use in a vent hole commonly found in metal molds which are used to produce, by rotational molding processes, a wide variety of plastic goods. The main body of the vent tube assembly is produced from a heat resistant, thermoplastic composition. Preferably, the composition will be polyetheretherketone (PEEK). The vent tube assembly resembles a probe-like rod comprising: a large diameter annular top section; an annular mid-section that is substantially smaller in diameter than the annular top section; and an annular bottom section that is slightly smaller in diameter than the annular mid-section and that terminates in with a rounded innermost tip. An elongated central bore is provided through the vent tube assembly. The central bore, along with a counterbore located near the top of the annular top section, provides an air escape passageway. The passageway fluidly communicates with the interior of the mold via a plurality of pore-like holes situated near the innermost tip.

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.