Abstract: A process for distributing wax or a similar substance in semi-solid form which uses a liquid wax supply system, a wax conditioning system including a heat exchanger which cools the wax to a semi-solid state and an accumulator for storing conditioned wax until needed, and a die press or similar work station which receives semi-solid wax from the accumulator in a continuous stream or flow. Such a system allows a lost wax die press to operate without need to manually open and reload the press with wax. An automated control system according to the invention allows die press reloading to occur automatically when needed, and operates the wax conditioning system as needed to maintain a supply of wax in the accumulator. Wax tunnelling problems are avoided by means of a piston disposed in the heat exchanger which is movably interposed between hot liquid wax entering the heat exchanger and cooler, semi-solid wax leaving the heat exchanger.

Abstract: In a mold for producing injection molded parts, the supply conduits for supplying molten material to the mold cavity are heated by various heating devices. Temperature measuring devices are provided for determining the temperature at predetermined locations within the melt flow. For the purpose of controlling the various heating devices depending on the predetermined temperatures at the individual measuring points, there is removably fixed to the mold at least one regulating member which is electrically connected via an electrical connector socket with electrical conduits installed within the interior of the mold. The electrical conduits installed within the interior of the mold are lead to the various heating and temperature measuring devices. The regulating member can be connected via an external conduit with a data supply and indicator member. The regulating member as well as the data supply and indicator member are preferably equipped to store several programs.

Abstract: A mold removing apparatus for removing a mold from a cylindrical molding sticking to the external circumferential surface of a mold, the mold being hollow, having center bores at the center of both the top and the bottom thereof, and having a plurality of small through holes in the circumferential wall thereof.

Abstract: In a heating/cooling unit for selectively heating or cooling a set of dies, oil received in a reservoir is supplied to a flow direction changeover valve by a first oil pump. In a stably mode, oil is returned to the reservoir through the changeover valve and a heat exchanger. In a heating mode, the oil is supplied to a second oil pump from the changeover valve through a check valve. The second oil pump supplies the oil to an oil heater, and the heated oil is introduced into a fluid path formed in the dies to heat the dies. The oil discharged from the fluid path of the dies is returned to the second oil pump. Thus, the heated oil is circulated in a closed loop in the heating mode. In a cooling mode, new oil is supplied to the fluid path of the dies from the changeover valve and the oil discharged from the fluid path is guided to the heat exchanger through a switching valve and the cooling oil is returned to the reservoir.

Abstract: A sprue bushing which has improved heat transfer characteristics and a method of making the same are described. A cylindrical bushing body having a first, preselected uniform diameter has a cavity formed therein which axially extends within the bushing body for a predetermined length. A bushing inner core which has an outer layer or sleeve of a high heat conductive material is formed in the cavity extending between the two ends of the bushing body. A heating element in the form of a ceramic insulator sleeve is inserted into the bushing body cavity and a particulate refractory material is deposited into the cavity to fill the remainder of the cavity. When filled, the bushing body is swaged down to a second preselected uniform diameter to compact the powdered refractory together with the preformed sleeve to form a solid heating element. A runner passage is then drilled through the inner core.

Abstract: A multilayered insulated mold structure is provided. An insulation layer provided on each of the mold cores retains heat at the molding surface, thereby increasing surface quality of the finished part. The insulating layer has a varying density across its thickness so as to have a low density center region and high density surface regions. By having a relatively low denisty, the center region of the insulating layer has a low thermal conductivity. Thus, the insulating layer may be made from the same material as the core and still have an acceptable insulating value. The use of the same material for adjacent layers reduces the potential of delamination of the layers. The multilayered mold is compatible with passive or active heating of the molding surface.

Abstract: This relates to a mold for rebonding polyurethane and like plastic foam to form selected shapes. A typical shape may be a back or a seat member for an article of furniture. The mold is improved in that the bottom mold member, which is particularly designed in accordance with the desired configuration of the shape, has been formed of epoxy which is readily moldable at a low cost. The mold is also improved by providing the base plate of the mold with a ramped floor which facilitates the drainage of condensate from a lower steam chamber. The configuration of the ramped floor allows for quick removal of the condensate and serves to reduce the volume in the steam chamber thereby minimizing pressure build-up in the steam chamber. This results in lower steam pressures being used during the curing process and for a shorter curing operation. The lower steam pressure also avoids leakage of steam and water from the epoxy mold.

Abstract: A nickel shell for molds formed by nickel vapor deposition having incorporated therein a combination steel parting line and manifold and a plurality of heating and cooling lines operatively connected to the manifold for the flow of heating or cooling fluid therethrough, said heating and cooling lines, and other mold components such as injection nozzles and mold vents, being encapsulated within the nickel shell.

Abstract: An injection mold typically defines multiple cavities. A mold gate is provided which comprises a rotary spherical member having a sprue conduit extending transversely therethrough. Highly accurate sequential molding of multiple cavities can be achieved in this manner, as well as other advantages. Also, this arrangement permits a linear, straight sprue conduit which is free of any sharp turns.

Abstract: A resin molding apparatus for molding an insulating resin mold at the peripheral portion of a semiconductor wafer has an upper metallic mold, and a lower metallic mold which clamps the semiconductor wafer with the upper metallic mold. The upper and lower metallic molds form a resin space at the portion corresponding to the peripheral portion of the semiconductor wafer. The contact surfaces of the upper and lower metallic molds, which are in contact with the semiconductor wafer, and the inner surface of the resin space are coated with elastic material which does not adhere to the insulating resin.

Abstract: A compact injection molding melt distribution manifold. The manifold has integral or monolithic inlet and main portions and both portions have a common electrical heating element. A melt passage extends through the manifold from a common inlet in the inlet portion and branches in the main portion to a number of spaced outlets leading to different gates.

Abstract: Injection molding apparatus wherein a heated probe extends into a well in a cavity plate having a generally spherical forward end. The forward end of the heated probe has at least one conical tip which extends outwardly at an angle into a conical recess leading to the gate. Each conical recess has an included angle of at least 90.degree. and the conical recess and conical tip extend outward along the same central axis at an angle to the longitudinal axis of the probe. This allows the tip to extend fully into the recess without intefering with withdrawal for cleaning or repair. The included angle of the conical tip is substantially less than the included angle of the conical recess which gradually accelerates the flow of melt as it approaches the gate.

Abstract: Molding apparatus, for example for molding components of polymerized resin without drawing, comprises a mold defined by a mold wall having a first thermal expansion coefficient, and a die including a die wall having a second thermal expansion coefficient greater than the said first coefficient, a molding operation being carried out by inserting the die into the mold at a first temperature, heating the die and the mold to a second temperature higher than the first temperature, and subsequently cooling the die and the mold after a component has been molded. In accordance with the invention, the die wall includes a plurality of separate sectors which are pivotally mounted on a common support member and which are arranged and dimensioned such that, at the second temperature, the radially outer faces of the sectors adjoin one another contiguously to define the molding face of the die wall.

Abstract: Rapid cooling of molded workpieces formed in an injection molding machine such as PET parisons is provided by a receiver receiving molded workpieces upon ejection from the molding machine, the receiver being transported out of the molding machine to an adjacent position where a cooling head coupled to a source of cooling fluid such as liquid CO.sub.2 directs the fluid toward the surfaces of each workpiece. The cooling head engages and is sealed to the receiver to inhibit the escape of cooling fluid into the atmosphere thereby reducing cost, environmental impact, etc. A sensor coupled to a control of the cooling fluid source permits the release of cooling fluid from said source to contact the workpieces only when the cooling head is engaged with and sealed to the receiver. A vacuum unit withdraws cooling fluid from the receiver subsequent to contact between the workpieces and the cooling fluid. The cooling fluid is then recooled and recycled for reuse.

Abstract: A rubber injection press with a stationary clamping table with a mould element and with a carriage with a further mould element, which carriage is movable in a direction towards the clamping table to close a mould formed by the two mould elements, has a heater associated at least with the stationary mould element and provided in the form of a heating panel, which is arranged between it and the clamping table and in which heating elements are arranged. So as to achieve a good heat transfer from the heating elements to the heating panel with, at the same time, the breakdown frequency being reduced and there being a wide range of design possibilities regarding the arrangement of the heating elements, the latter are cast in the heating panel as heating coils. Thus it is possible also to arrange rapid clamping devices in the heating panel.

Abstract: A predetermined amount of melted thermoplastic resin of raw material is injected into a molding space which is previously set to a temperature higher than that at which the resin beings to harden under atmospheric pressure and which has a capacity larger than a volume of a product. The injected resin is cooled in the molding space and pressurized before the resin is cooled to the temperature at which the resin begins to harden under atmospheric pressure. When pressurized, the glass transition temperature of the thermoplastic resin is shifted to a higher temperature so that the thermoplastic resin hardens in slight reduction of the temperature. The resin is cooled in the pressurized state until the resin possesses the dynamic rigidity under room temperature and atmospheric pressure.

Abstract: The sprue bushing is mounted within a support housing for an injection molding machine. Melt viscosity of plastic employed is controlled by moving water through the bushing inner tube during the presence of the plastic. The bushing has an outer sleeve containing a longitudinal central bore. An inner tube is mounted within the bore, but spaced apart from an inner wall of the bore. Baffles mounted on opposite sides of an outer wall of the inner tube prevent water movement around an upper portion of the tube. A lower portion of the tube having a smaller outer diameter than the upper portion permits the water to flow under the baffles and through the bushing.

Abstract: A cast manifold for distributing pressurized melt in an injection molding system. The melt is received at a central inlet on the rear surface of the manifold to an inlet portion of a melt passage. Four identical outlet portions of the melt passage branch radially outward from the inlet portion to equally radially spaced outlets on the forward surface of the manifold. Each outlet portion extends around a first smoothly curved bend from the inlet portion, along a radial portion, and then around a second smoothly curved bend to the outlet. By casting on a removable ceramic mold, the bends in the melt passage are very smoothly curved and do not all have to extend in a common plane. Furthermore, the radial portions angle a substantial distance rearwardly as they extend outwardly which allows the thickness of the manifold to be reduced.

Abstract: A plastic mold (A, B) for rotational molding are disclosed. The plastic mold, used in lieu of a conventional metal mold, is constructed from a fiber (52) reinforced thermoset plastic resin (50) having a heat distortion point above the melt point of the thermoplastic polymeric material from which an article is molded. Metal (64, 70, 74) or other dissimilar material may be used to provide different coefficients of heat transfer at preselected portions of mold (A, B). The entire mold may include a thermal coefficient modifier to increase the heat transfer rate of the mold uniformly over the entire mold in addition to the preselected portions.

Abstract: A molding assembly comprising a molding apparatus defining a mold cavity, a fill gun communicating with the mold cavity, and a clamp assembly mounted on the molding apparatus for clampingly engaging the fill gun.

Abstract: Optimum sprue design requires suitably large cross-sectional area of the open aperture during mold filling and packing yet fast heat removal from the molten sprue during solidification. This is accomplished by a "hollow" sprue configuration, wherein an enlarged female sprue bushing cavity of large draft angles is axially aligned with a "spreader die" type of male member having a generally conical-tipped or parabolic-tipped torpedo shape, creating a cross-sectional open aperture consisting of an annular ring along at least partway up from the base to the tip. Both male and female may be fitted with internal mass-transport cooling. Since the cooling time of the sprue is directly proportional to the wall thickness of the molten plastic sprue being formed, and cooling time is further inversely proportional to the plastic/mold surface area, the resulting "hollow sprue" provides superior cooling without impaired fill and pack function.

Abstract: A tool for the injection molding of synthetic plastics to form a plastic top on a paper tube container has an inner mold and a two-part outer mold in which two steel mold parts are adapted to be applied against each other in sealing-tight manner along a plane of separation and moved away from each other again. The injection molding cavity is formed by a surface contour attachment disposed on the mold parts. Cooling spaces are disposed behind the surface contour attachment on the side remote form the injection molding cavity.

Abstract: The method and apparatus for injection molding of continuous molded products employs a single endless flexible mold band having multiple injection ports revolving in registration with a rotating cylindrical mold member. This cylindrical mold member comprises a wide wheel rim or a circumferential wall on a rotating drum. Continuous mold cavities extend in parallel relationship circumferentially around the periphery of the cylindrical mold member. Injection ports in the mold band are kept in alignment with these mold cavities by sprocket teeth of the mold member engaging with sprocket holes in margins of the band. Fluid plastic material (either thermoplastic material or thermosetting material) is injected through these ports into the mold cavities. When injecting thermoplastic material, heaters warm the cylindrical mold member and band prior to injection; then coolers chill them for cooling the thermoplastic material for solidifying it.

Abstract: An injection mold apparatus has an injection mold which includes two mold halves incorporating thinwalled members to define a cavity therebetween. Before injecting plastic material into the cavity, the mold is heated to a temperature above the melting point of the plastic material by circulating a heat carrier flowing through a heating device. During injection of plastic material, the flow of heat carrier is stopped for maintaining the temperature of the mold and for supporting the thinwalled members. After completely filling the cavity, the mold is cooled down to a temperature below the freezing point of the plastic material by suitably circulating the heat carrier which now passes through a cooling device.

Abstract: A process for manufacturing moldings of plastic material includes successive cycles of conveying a succession of mobile molding tool parts independently of each other along lateral and vertical guideways of a conveyor to a work station holding a basic molding tool part.

Abstract: A method for the injection moulding of unsaturated polyester resin masses includes the steps of compacting the moulding mass in an accumulation cylinder, generating a subatmospheric pressure in the cylinder and heating the compacted mass at subatmospheric pressure by the application of a high-frequency load as it passes between the inner wall of a hollow metal cylinder and a coaxial spaced cylindrical electrode and injecting the material into the die. The apparatus for carrying out the method includes an accumulation cylinder of metal having a coaxial cylindrical electrode mounted therein to define a substantially hollow cylindrical passage for the flow of the resin mass. A generator is connected to the electrode to generate high frequency waves to heat the resin mass passing over the electrode.

Abstract: An injection moulding apparatus (10) includes similar co-injection modules (12) each provided with common supplies (238-242) and supplied with different polymer materials at intermediate pressure by common plasticisers (14-18). Each module has a co-injection nozzle assembly (70) in wich each nozzle (148-154) is supplied with polymer at injection pressure by an injector (208) which receives polymer through a non-return valve (220). The injector is mounted alongside the nozzle on a polymer transfer plate (138-146), and has the position of its piston (212) controlled by a hydraulic actuator (214) under the control of a dedicated micro-processor (164) in accordance with a stored injection control program. Each polymer is injected by an injector (208) directly into the associated nozzle (148-154) and is controlled solely by injector operation, and without the use of any control valve between the injector and the nozzle.

Abstract: A nozzle located in an injection mold for injecting a first medium into a mold cavity containing a second medium. The injection molding has a first bore connected to a first mold surface via a second bore. An outer blowing needle having a first terminal end is located within the first and second bores. An inner blowing needle having a second terminal end is located within the outer blowing needle and has at least one opening near the second terminal end which communicates with the second bore.

Abstract: A method and an apparatus for injecting a steam into a mold in an injection molding machine by injecting a desired stream toward the opening of the metal mold including a gate and cavities in connection with the opening and closing operation of the metal mold thereby intending the cooling solidification of the molten resin on th gate portion and simultaneously intending removal of dewing and an oily matter on the surface of the metal mold.

Abstract: A device for the injection of a plastic material in a mold having an injection head with an injection face designed to be placed in contact with the mold feeder channel. The injection head has an injection chamber supplied with plastic material by a feeder conduit. The plastic material is injected from the injection chamber to the mold feeder channel by means of a clack-valve system. The device also has a support for the injection head and an injection rod.

Abstract: A die assembly for die casting a propeller structure, such as a wax propeller pattern. The pattern, which is identical in configuration to a cast metal propeller to be produced, includes a generally cylindrical hub having an outwardly flared end and a plurality of blades project outwardly from the hub. The die assembly includes a base plate and a lower core section extends upwardly from the base plate through an opening in a stripper plate, which is mounted for movement toward and away from the base plate. A plurality of die sections are mounted for generally radial sliding movement on the stripper plate from an outer open position to a closed position where they define a die cavity with the core section. The die assembly also includes an upper die unit that is mounted for vertical movement and has a cavity in its lower surface which receives the upper ends of the die sections when in the closed position.

Abstract: A system for distributing wax or a similar substance in semi-solid form is provided which includes a liquid wax supply system, a wax conditioning system including a heat exchanger which cools the wax to a semi-solid state and an accumulator for storing conditioned wax until needed, and a die press or similar work station which receives semi-solid wax from the accumulator in a continuous stream or flow. Such a system allows a lost wax die press to operate without need to manually open and reload the press with wax. An automated control system according to the invention allows die press reloading to occur automatically when needed, and operates the wax conditioning system as needed to maintain a supply of wax in the accumulator. Wax tunneling problems are avoided by means of a piston disposed in the heat exchanger which is movably interposed between hot liquid wax entering the heat exchanger and cooler, semi-solid wax leaving the heat exchanger.

Abstract: An apparatus for high frequency molding by injecting a liquid plastic material under pressure into a mold, while simultaneously venting the inside cavity of the mold, optionally by applying to suction. In order to overmold and/or mold onto a prisoner a part in the form of a closed loop, a sealing insert (i) is disposed between the openings into the mold for its injection nozzle (17) and its venting nozzle (18). The shape of the insert corresponds to the profile of the mold, and the insert is made of a material having the same nature as the injected plastic material, such that the insert melts and is welded to the molded or overmolded part when the high frequency electric field is applied by means of an appropriate generator. The injection and the venting nozzle are controlled by respective double action actuator devices fitted with pistons and piston rods made of a material which does not exhibit dielectric loss, and forming a removable unit assembly.

Abstract: A mold mounting apparatus having a mold holding apparatus provided on one side at the end of rails, for positioning and holding a mold; a second mold holding apparatus provided on the opposite side of clamping machines of an injection molding machine and the rails, for preheating, positioning and holding the mold in place; a mold delivery apparatus for delivering the mold to two clamping machines; and a mold carrying apparatus for receiving and delivering the mold among the mold holding apparatus, the second mold holding apparatus, and the mold delivery apparatus, and for conveying the mold along the rails. According to this mold mounting apparatus, the mold can be automatically carried into, and out of, all of the clamping machines after the mold has been brought into the mold holding apparatus, thereby improving mold changing operation efficiency and saving a space for the molding process.

Abstract: A cooling apparatus for an injection molding machine, which is used to form hollow parts, employs mating mold dies with first and second corresponding hollow core members attached to the dies and extending into the mold cavity. When the cavity is closed, the hollow core members engage to form a continuous cooling fluid passageway through them. During the molding operation, liquid cooling fluid is supplied under pressure to flow through this passageway. At the end of the molding cycle, the flow of cooling fluid is blocked and a second valve is opened to admit air into the passageway near the point where the two hollow core members engage. A vacuum is applied to the opposite ends of both of the hollow core members to pull any cooling fluid and air from the junction between the core members and away from the junction back through the core members.

Abstract: An investment casting wax injection machine includes a heater for heating wax. A cylinder with a piston is disposed in the container which is disposed beside the working table. A discharge pipe connects the heater and the container for supplying the melted wax from the heater to the container. A disc is fixed at a bottom end of the cylinder. A number of check valves are provided on the piston and the disc. A distributor with a nozzle is disposed on the cylinder, and a check valve is provided between the distributor and the cylinder. A number of cooling manifolds are distributed in the distributor for cooling the wax.

Abstract: An injection molded plastic article is produced by introducing a stream of molten plastic material from an injection molding machine cylinder into an article forming mold space. Pressurized gas is supplied into the interior of the molten plastic material to form a gas containing cavity therein. The plastic material is then allowed to solidify and cool sufficiently so that the article can itself sustain the form dictated by the mold surface. The cavity is vented to reduce the pressure within the cavity to ambient pressure prior to opening of the mold.

Abstract: An ohmically or electrothermally controlled valve gate for injection molding apparatus comprises three concentrically located tubes in intimate contact with each other. The innermost tube is an electrode and also serves as the passage for flowing molding material. The outermost of the three tubes is also an electrode. The intermediate tube is a resistive heating element comprising a mixture of at least two highly compacted powders. One powder is an electrical conductor, while the other powder, which serves as a binder for the first powder, is an electrical insulator but a good thermal conductor. Current flow between the electrodes occurs at points of contact between adjacent particles of the conductive powder. Thus, the electrical resistance and therefore the generation of heat is controlled by the composition and quantity of binder in the heating element. The generated heat is conducted through the inner electrode tube to the flowing plastic to melt the plastic and "open" the gate.

Abstract: An apparatus for injection moulding plastics closure elements into apertures in the central panels of a plurality of can ends comprises a first mould tool, a second mould tool, and a mechanism for bringing the mould tools together to clamp on opposed surfaces of each central panel and thereby define a mould cavity enclosing a margin of panel material around the aperture and spanning both sides of the aperture. A passageway in at least one of the moulded tools permits injection of plastics material into the mould cavity. The first mould tool includes a plurality of cavity defining mould portions each slidably guided in a respective bore in the first mould tool and a resilient support in each bore to urge each mould portion towards the second mould tool. A stripper plate surrounds the mould inserts and is formed with an annular recess situated laterally outside of and around each insert to receive the outer circumference of a can end to properly locate the can end.

Abstract: A unitary injection molded filter is disclosed which includes a rigid frame of resin material to provide a rigid shape to the filter, and at least one screen of non-woven sheet resin material suspended on the frame and having formed therethrough a plurality of holes extending between the opposed side surfaces of the screen so as to form fluid passages therethrough. Each screen is integrally molded simultaneously with the frame.

Abstract: A rubber shaping machine includes an upper mold, an upper middle mold, a lower middle mold, and a lower mold operated by a main oil cylinder and two auxiliary cylinders so as to open the mold in multi-steps. The machine also includes a feeding system capable of being suitably heated and cooled to facilitate the changing and cleaning of the rubber material therein and capable of preventing the rubber material from being hardened. An injection head device is disclosed which prevents the rubber material from being split.

Abstract: A porous die includes a porous die body with a plurality of pores formed therein; a cooling chamber provided in direct contact with the back side of the porous die body in order to cool the porous die body; a device for supplying a coolant to the cooling chamber; and suction holes through which the cooling chamber is evacuated and the air and the coolant entering the cooling chamber are simultaneously sucked.

Abstract: An injection molding machine has an injection molding unit shiftable parallel to itself into a selected working position, dependent upon the location of the injection opening of the mold closing unit. The latter includes a stationary mold carrier having parts defining guide grooves oriented transversely to the injection axis. The injection molding unit has hydraulic power cylinders arranged symmetrically to the injection axis. Each hydraulic power cylinder has a piston rod on which the injection molding unit is supported. Each piston rod has a coupling terminus received in a respective guide groove for guiding the respective piston rod therein during motion of the injection molding unit between working positions. The coupling terminus of each piston rod is prevented by the respective guide groove from moving in a direction parallel to the longitudinal axis of the respective piston rod, whereby the piston rods are axially immobilized.

Abstract: An injection molding machine has a mold closing unit arranged on a machine bed and adapted to selectively receive a first type of mold assembly having a central injection opening or a second type of mold assembly having a non-central injection opening; a platform mounted on the machine bed; and an injection molding unit supported on the platform. The injection molding unit includes a carrier block; a plasticizing cylinder received in the carrier block and a feed screw received in the plasticizing cylinder. The injection molding unit is pivotal by a drive into a first working position in which the injection molding unit cooperates with a mold assembly of the first type or into a second working position in which the injection molding unit cooperates with a mold assembly of the second type. The platform has two parallel-spaced side plates which flank the carrier block.

Abstract: A multi-cavity mold in combination with a hot runner system wherein the hot runner system includes metering means individual to each mold cavity for feeding precisely measured quantities of thermoplastic material to each cavity.

Abstract: A press for moldinig thermoplastic, thermosetting, polyurethane polymeric articles comprises three workstations arranged side by side and including a central molding station and two lateral stations for cooling and extracting molded articles. Two molds are rigidly connected to one another and controlled by a transfer pusher which alternately moves the molds from the molding station to either of the cooling and extraction stations. A first presser at the central molding station applies a closure pressure necessary for the material injection, while auxiliary presser arranged in each station applies a reduced secondary pressure to the molds at the end of the injection step, during the translatory motion of the mold and during the cooling step.

Abstract: A heated channel for use between a clamping plate and a mold plate of a plastic injection machine. The heated channel includes a heated-channel member having longitudinal bores with cross bores for connecting the connecting and branching nozzles thereon. An insert member with material-guiding bores therein for providing the connection of the nozzles in the clamping plate and the mold plate is inserted into the longitudinal bore. The insert member is provided with grooves for receiving heating elements. Connecting elements for the radial and axial fixing of the heated-channel member and the insert member are inserted into the heated-channel member.

Abstract: A method and apparatus for the fabrication of optical lenses by injection/compression molding of thermoplastic includes a plurality of sleeves, each having a bore therethrough, and a plurality of mold inserts dimensioned to be received in the bore with minimal clearance for sliding fit. The mold inserts each include a precision optical surface adapted to form a front or back surface of a lens. A selected pair of mold inserts are placed in the bore of a sleeve with front and back surface forming optical surfaces in confronting relationship to define a mold cavity, and the assembly is heated to a temperature above the glass transition temperature of the thermoplastic to be molded. An injection port extends through the sleeve to the bore, and is positioned to inject thermoplastic that has been heated to a fluid state into the cavity. After injection of the thermoplastic, the mold inserts are compressed together, and excess thermoplastic is forced out of the mold cavity.

Abstract: Thermoplastic parts are formed by a process that produces at least one surface that is a direct replication of the mold surface without secondary operations, e.g., a "Class A" surface. The process is particularly suitable for the production of large parts such as automobile panels, refrigerator panels and the like especially those employing a high-viscosity resin and particularly those parts made by blow-molding. The process comprises pressing at a selected pressure a plastic preform heated above the glass transition temperature (Tg) against a suitably smooth or detailed mold surface held at a temperature below the Tg of the resin; raising, preferably rapidly, the mold to a temperature above Tg for the time necessary to raise above Tg a depth of resin sufficient to remove surface imperfections, die lines, and pores, and fill voids, and substantially embed included matter; and rapidly cooling the mold until the molded part is below Tg when pressure may be released and the mold opened.

Abstract: The apparatus includes a carrier plate cooperating with an injection molding machine and having at least two sets of cavities therein for cooling the hollow plastic articles, with the number of cavities corresponding to a multiple of at least two times the number of hollow plastic articles produced in an injection molding cycle. The apparatus also includes means for aligning one set at a time of said carrier plate cavities to juxtapose said set of cavities with the hollow plastic articles formed in an injection molding cycle, and means for transferring said hollow plastic articles to said juxtaposed cavities.