Abstract: A method of sandwich molding, in which a first thermoplastic material is injected into a mold cavity followed by the injection of a second thermoplastic material expanding within the first thermoplastic material, eliminates the need for heated runner systems communicating from the injection nozzle of the injection molding machine to the mold cavity by employing a cold runner having sufficiently slow solidification time to allow subsequent injections from two injection sources. The backflow into the inactive branch is prevented by maintaining the injection nozzle against the mold until molding is complete.

Abstract: An injection molding apparatus and method for multi-layer molding of preforms and closures has a central melt channel, an annular melt channel radially spaced from the central melt channel, and an annular ring channel surrounding the central melt channel. The central melt channel has a first portion for flow of a first material, a second portion for flow of the first material and a second material, and a flow extension connecting the first portion and the second portion. The flow extension has a flow opening in communication with the annular ring channel for flow of the second material. The apparatus and method also include a cavity for receiving flow of the first material and the second material from the central melt channel, and for receiving flow of the first material from the annular melt channel. In addition, the apparatus and method include a melt passage having a first melt portion in communication with the central melt channel, and a second melt portion in communication with the annular melt channel.

Abstract: An injection molding apparatus and method for multi-layer molding of preforms and closures has a central melt channel, an annular melt channel radially spaced from the central melt channel, and an annular ring channel surrounding the central melt channel. The central melt channel has a first portion for flow of a first material, a second portion for flow of the first material and a second material, and a flow extension connecting the first portion and the second portion. The flow extension has a flow opening in communication with the annular ring channel for flow of the second material. The apparatus and method also include a cavity for receiving flow of the first material and the second material from the central melt channel, and for receiving flow of a third material from the annular melt channel.

Abstract: The present invention provides processes and an apparatus for injection-molding an article with a fluid channel formed therein. The process includes providing at least first and second resin streams within a mold cavity, causing the flow fronts (16) of the resin streams to meet at a longitudinal point in the mold cavity to form a first layer of solidified resin on a peripheral surface of the mold, the first layer having a knit line (20) at the longitudinal point where the resin streams meet; and introducing a fluid into the molten resin in the mold to form a fluid channel (50) and a second layer (32) of solidified resin, the second layer between the fluid channel and the first layer of solidified resin, wherein the second layer is devoid of a knit line at the longitudinal point in the mold cavity where the first and second flow fronts meet.

Abstract: The present invention is directed towards the hybrid combination of a drop gate injection molding system and a lattice gate. The lattice gate is located prior to the orifice of the drop gate. The lattice gate is comprised of a series of cross-direction flow channels through which the rubber flows, with mixing of the rubbers at the intersections of the flow channels. This hybrid molding system permits shorter cure times, and improved process cycle time for curing rubbers.

Abstract: A gear molding method for molding a plurality of plastic gears having a different number of ribs without changing costly gates uses a mold having a prescribed gear shape including a prescribed number of grooves substantially radially arranged in the mold. A prescribed number of gates is provided for pouring molten plastic into the mold. When a plastic gear is molded and separated from the mold, a prescribed number of grooves are additionally cut at a middle angular position between each of the pair of neighboring grooves without changing the gates. Then, another gear having increased number of ribs is molded using the same gates.

Abstract: The present invention is directed towards the hybrid combination of a drop gate injection molding system and a lattice gate. The lattice gate is located prior to the orifice of the drop gate. The lattice gate is comprised of a series of cross-direction flow channels through which the rubber flows, with mixing of the rubbers at the intersections of the flow channels. This hybrid molding system permits shorter cure times, and improved process cycle time for curing rubbers.

Abstract: A molding device and method utilizes a cavity including first and second parts for molding an article having one or more convex portions and a gate for injecting mold resin into the cavity. The gate in turn includes one or more gate sides for injecting resin into a concave portion of one part and a gate base for injecting resin into a second of the parts in which no concave portions are located, both resin injections occurring simultaneously and substantially encapsulating a semiconductor element to form a molded article having a convex lens.

Abstract: The invention relates to a method of producing an automotive vehicle body part (1) by injecting a plastics material sequentially into a mold fed by one or more cold runners, the method consisting in filling firstly a first region (A) at one end of the mold, then a second region (B) adjacent to the first region, and repeating the operation consisting in filling a new region adjacent to the preceding region each time, until a last region (C) of the mold is reached at its end opposite from the first region (A). Each cold runner is shut off using a cold rod which is axially movable in a bore intersecting the cold runner, the longitudinal section of the rod overlaying the cross section of the runner.

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

Abstract: The nozzle is constituted by a nozzle body and a connecting block. The nozzle body is constituted by a casing and a core. A first passage is formed in the center of the core and a second passage is formed between the external surface of the core and the internal surface of the casing. The first passage and the second passage join together in front of the core and then lead to a discharge port at the tip end of the casing. In the interior of the connecting block are formed a first supply line and a second supply line. The first supply line connects a sub injection unit to a first supply port, and a first stop valve is provided within the line. The second supply line connects a main injection unit to a second supply port, and a second stop valve is provided within the line.

Abstract: A molding method and a molding die for producing a lens of a vehicular lamp wherein the lens has an improved appearance in that no weld lines are formed on the surface of the lens and the lens consequently has an improved mechanical strength. The molding die has a gathering area for molten resin in the molding cavity in a flow region of the molten resin to be formed into a lens. A heat insulating layer is formed on a cavity face on the side of the lens surface at the gathering area for the molten resin in the molding die, as a result of which instantaneous cooling is prevented. Accordingly, a skin layer formed on the side of the lens surface at the gathering area is very thin, thereby preventing the generation of a weld line, which could otherwise be generated if thick skin layers produced when high-temperature molten resin directly comes into contact with steel material and cooled instantaneously are gathered together.

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

Abstract: An injection molding apparatus is provided in which the rate of material flow during the injection cycle is controlled. According to one preferred embodiment, a method is provided for use in an injection molding apparatus including a hot runner assembly comprising a manifold and at least first and second injection nozzles, the hot runner assembly to direct material injected into said manifold through said at least first and second injection nozzles through a corresponding at least first and second gates to one or more mold cavities. The method includes the steps of injecting material into the manifold, controlling, in the hot runner away from the first gate, a first rate at which material is injected through the first gate, and controlling, in the hot runner away from the second gate, a second rate at which material is injected through the second gate, independently from the first rate.

Abstract: The invention relates to a process for manufacturing injection moulded objects of thermoplastic material by injecting molten thermoplastic material into a mould from at least two distinct injection points whereas the flows of molten material from each injection point each fill part of the mould and flow together to fill the entire mould while still in molten state, wherein objects having a size of more than 80 cm along each of its three dimensional axes are produced by providing at least two distinct injection points at opposite sides of the mould. The invention also relates to injection moulding equipment for the manufacture of moulded objects of thermoplastic material, comprising at least two distinct injection points provided at opposite sides of a single mould assembly. The invention further also relates to three dimensional moulded objects of thermoplastic material having a size of more than 80 cm along each of its three dimensional axes.

Abstract: An apparatus for controlling the rate of flow of fluid material through a flow channel having an exit aperture leading to a mold cavity, the apparatus comprising:

Abstract: A combination rubber injection gate system (24) and method of injection molding rubber to produce desired flow patterns in the rubber is disclosed. The combination gate (24) directs rubber through a first region (26) to flow at cross angles (38, 40) through the injection gate (24), relative to the direction of flow of the rubber (22) through the injection gate (24). The rubber (22) is then directed through an adjacent region (28) to flow through the injection gate (24) at a direction parallel to the direction of flow of the rubber (22) through the entire injection gate (24). The combination gate (24) yields a highly mixed and uniform flow of rubber (22) that is particularly useful when injection molding fiber-loaded rubber where it is desired to orient the fibers in a particular direction.

Abstract: The present invention relates to a lattice gate for directing streams of rubber into an injection molding device through a plurality of intersecting channels (78, 80) which thermally mix the streams of rubber within the gate (76) as they pass through the intersections of the flow channels permitting the injection time of the rubber into the mold cavity to be decreased while simultaneously reducing the time for curing the rubber within the mold.

Abstract: Trim panels for motorvehicles are manufactured by: injection molding a panel base portion having missing parts of predetermined area and shape, said molding involving the coinjection of a surface material and of an inner core material; separately producing a plurality of portions of panel having area and shape substantially corresponding to the missing parts and fastening said separately produced portions to said panels.

Abstract: An injection unit for injecting plastic into a cavity of a mold includes an injecting device connectable between an extrusion die and the mold. The injecting device includes a mouth having a plurality of openings that is insertable into the mold so that the plastic flows through the plural holes into the mold. A drive is connectable to at least a portion of the injecting device for rotating the mouth portion and the plural opening of the injecting device about a central axis as the plastic flows through the holes into the mold.

Abstract: A injection molding device for manufacturing golf balls is disclosed. The device includes first and second hemispherical mold halves that form an interior cavity where the injection molding process occurs. A plurality of retractable pins are preferably used to support a core within the mold cavity. The first and second mold halves further include a plurality of subgates. The subgates are connected to a runner system for delivery of a fluid stock material into the void of the cavity. The plurality of subgates includes a first and second set of subgates. The first set of subgates and the second set of subgates enter the respective cavities at an angle between 30 and 40 degrees to the parting line.

Abstract: Hard to fill large-surface-area parts and/or thinwalled configurations of optical lenses and reflective optical elements are among the difficult-to-mold thermoplastic products which require precision replication of the molding surfaces, in micro detail. We combine multiple opposing gates (to reduce the meltflow pathlength) with non-isothermal steps of firstly, heating these mold surfaces (with circulating heat transfer fluids supplied by a hot side supply system, to a temperature setpoint sufficiently high to retard solidification), then secondly, injecting the melt through these opposing gates, then thirdly, rapidly cooling to solidification (by circulating heat transfer fluids of much lower temperature, supplied from a cold side supply system).

Abstract: An injection molding apparatus for producing formed or molded millwork products includes a workstation supported on a support surface, a lower composite mold/press unit mounted upon the workstation and defining a lower portion of a mold cavity, and upper composite mold/press unit defining an upper portion of the mold cavity, and support members spaced apart from one another along the lower composite unit, movably mounted to the workstation, and extending above the lower composite unit where the support members mount the upper composite unit generally above and for movement toward and away from the lower composite unit. Either of the lower and upper mold/press units can have replaceable plates for different shaped products. The apparatus also includes actuators for the support members and releasable locking mechanisms for the upper composite unit.

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

Abstract: A mold assembly for making a multilayer molded article comprising: a first mold; a second mold; a shut-off pin slidably received in a resin-supplying gate opened to a cavity face of the first mold; a pin-driving unit for moving the shut-off pin among an opening position, a closing position and a projecting position; a resin-supplying unit for supplying a molten thermoplastic resin from said resin-supplying gate; and a press unit for moving the molds between an open position and a closed position.

Abstract: A method and apparatus for making a multi-colored, injection molded product. A nozzle which has at least two separate feed passageways receives the primary resin stream from the primary feed tube. Two separate fluid-operated cylinders add different colorant masses to the separate portions of the feed stream through lateral openings into the two passageways. Blending of the two different masses is prevented in the nozzle and blending with the primary resin stream is minimized during feed to the mold to optimize the brightness of the colors in the end product.

Abstract: An injection mold for golf balls defines a spherical cavity therein and has a parting plane extending coplanar with the equator of the cavity. A plurality of molding material injecting gates are arranged in the mold body along or near the cavity equator, and a plurality of retractable core support pins are disposed in the mold at areas other than the cavity equator and poles so that the core support pins may be moved toward and away from the cavity center. A cover having a uniform gage and a smooth surface can be injection molded to produce a golf ball without radial misalignment of the core.

Abstract: There is provided a process for producing a multi-layer molded product having a plurality of thermoplastic resin layers. This process provides for (i) a step of supplying first and second molten thermoplastic resins each through first and second resin supplying gates which are temperature-controllable independently of each other, to between female and male molds kept in an open state with a time difference being provided between supply starts of the first and second resins, and (ii) a step of closing the female and male molds after completion of supply of the first and second resins. The process enables production of high-quality multi-layer molded products having a plurality of resin layers with good repeatability under relatively low resin supply pressure and by single mold closing. Further, high-quality multi-layer molded products can readily be produced without restrictions on materials used.

Abstract: An injection molded product, having an array of fastener elements integrally molded with and extending from a surface of the product, is molded in a closed cavity die. One half of the die has a mold surface with a region having an array of fastener element cavities extending therefrom for molding the fastener elements. The other half of the die has a mold surface aligned with the mold surface of the first mold part to define therebetween, in a closed condition, a mold cavity constructed to receive molten plastic for molding the product. The mold cavity includes a first portion comprising a majority of the volume of the mold cavity, and a second portion contiguous with the first portion and defined in part by the region of the first mold part surface having the array of fastener element cavities.

Abstract: A manifold for a multiple injection unit injection molding machine that allows the machine to be used when a standard conventional mold is attached to a platen. The manifold includes a first inlet port that is in communication with one nozzle of the machine and a second inlet port that is in communication with another nozzle of the machine. Each inlet port communicates with an inlet passage and the two inlet passages join an exit passageway at a junction. The exit passageway is in communication with an exit port to transfer fluid to a mold cavity. The manifold has a valve located at the junction to control the flow of material through the exit passageway.

Abstract: A golf ball mold includes a pair of mold sections which are removably mated along a parting line to define a spherical cavity by their concave surfaces which are provided with a plurality of dimple-forming projections. Some dimple-forming projections are located across the parting line, and molding material injecting gates or fin-forming pits are located near the respective projections. After a seamless golf ball having dimples on the parting line Is molded, any abrasion of the dimples on the parting line can be effectively avoided in the subsequent step of grinding off the fins and burrs.

Abstract: A multi-cavity coinjection mold having a relatively large plurality of cavities for simultaneously molding a relatively large plurality of multi-layered articles including a) a plurality of cavity groups each defining a relatively small plurality of said cavities, a single balanced hot runner for supplying said relatively small plurality of cavities with contiguous different plastics materials, and a valve for sequentially supplying desired contiguous quantities of the plastics materials from plastics material sources, common to all of said groups, to the balanced hot runner; and b) a hot runner manifold system connected to the plastic material sources to supply the plastic materials to all of the valves; and related methods.

Abstract: A golf ball mold includes a pair of mold sections which are removably mated along a parting surface to define a spherical cavity by their concave surfaces. The concave surfaces are provided with a plurality of dimple-forming projections. Some dimple-forming projections are integrally formed in one mold section at the parting surface as raised knobs that protrude in a transverse direction over a distance of 1/2 to 1/4 of the projection diameter, and the other mold section is provided at the parting surface with recesses for receiving the raised knobs. Using the mold, seamless golf balls with improved flight performance can be molded.

Abstract: A method and apparatus for molding a one-piece article in a single molding operation using two different plastic materials so a first portion of the article is made of one plastic material and a second portion of the article is made of a different plastic material, and the two portions are fused together while hot to create a one-piece article.

Abstract: An injection mold includes a pair of mold sections which are removably mated to define a spherical cavity by their concave surfaces, support pins disposed in the mold sections for movement into and out of the cavity, and gates connected to the cavity for feeding a cover molding material from an injection molding machine into the cavity. A golf ball having a core and a cover is prepared by supporting the core in the cavity by the support pins, and injecting the cover molding material between the core and the cavity-defining surface through the gates, thereby molding the cover around the core. The gates are oriented relative to the cavity such that the cover molding material is injected in a direction off the center of the core.

Abstract: A golf ball injection mold defines a spherical cavity therein. A parting plane is situated substantially at an equator of the cavity. A plurality of gates are disposed nearly along the equator. At least one gate is disposed nearly at a position corresponding to the cavity's north pole and at least one gate disposed nearly at a position corresponding to the cavity's south pole. A molding material is injected from an injection molding machine into the cavity through the gates. A steric arrangement of gates adapted to the cavity geometry permits a cover or intermediate layer of a uniform thickness to be formed around a core.

Abstract: A method of injection molding a golf ball that includes a core and at least one cover layer disposed thereon is disclosed. The method comprises the steps of centering a core in a molding cavity, injecting a molten material into the cavity around the core at a plurality of locations such that the material simultaneously exerts a force on the core at each location. The forces have components that balance the core in three dimensions. Injection continues until the material covers the core and solidifies thereon. An injection mold for forming the golf ball is also disclosed. The mold includes a plurality of pins extending from a spherical outer surface of a molding cavity. The mold further includes a plurality of runners having radially extending portions that are non-aligned and terminate at gates for flowing a molten material in a fluid state into the cavity, and a means for simultaneously injecting the material into the cavity from the gates. The gates are at spaced locations on the surface of the cavity.

Abstract: Golf balls are prepared using an injection mold defining a spherical cavity and having a plurality of gates for admitting a molding material into the cavity therethrough. The gates are arranged such that the maximum flow distance that the molding material admitted from each gate moves along the cavity-defining wall may be not greater than .sqroot.3.pi.r/4 wherein r is a radius of the cavity. Golf balls of quality having a cover with a uniform gage of 1 mm or less can be molded without short shots.

Abstract: A method and apparatus for injection molding a plastic cover. The method includes the steps of forming a mold having a relatively thin-walled, circular cross-sectional molding area concentric with and along a predominant axis of the mold and of a graded generally decreasing diameter of the cross-sectional molding area from a first end to a second end of the mold along the predominant axis, providing a plurality of passageways in the mold from a periphery of the circular cross-sectional molding area at the second end to an exterior of the mold, and filling the mold through the plurality of passageways.

Abstract: Apparatus for molding consecutive streams of differently and homogeneously colored resin in a single mold. The apparatus is used to practice a method including supplying molten resin to a selected one of a plurality of resin passages, injecting colorant selected from a plurality of different colorants into the resin passage, mixing the molten resin and colorant in a mixing element disposed in the resin passage to form a mixture of selectively colored resin, injecting the mixture into the single mold to form a part from the selectively colored resin, and repeating the process by selecting a different resin passage and a different colorant. By this apparatus and method, differently colored parts can be molded without purging the resin passages between the molding, of the parts.

Abstract: There is disclosed a die used to mold a cage having a cylindrical body out of a synthetic resin such that the strength of the portion of the molded cage formed by two meeting streams of the injected material is increased. The die comprises die members having parting surfaces in abutment with each other. A mold cavity conforming in shape with the cylindrical body of the cage is formed between the die members. When the die members, are in abutment with each other, a gate and a resin reservoir are formed along one parting surface and outside the mold cavity. The gate and resin reservoir are in communication with the cavity.

Abstract: For the shaping of a microstructure substrate via a mold cavity, an unmolding device allows an abrupt, shear-free separation, in particular at reaction temperature, of the microstructure substrate manufactured using the reaction molding method. Optical waveguide components meeting stringent damping requirements can easily be manufactured with this device.

Abstract: An injection mold for golf balls includes a pair of separable mold segments (1a, 1b). The mold segments (1a, 1b) are mated at their peripheral surfaces (12) along a parting line so that their inner surfaces (2a) define a spherical cavity (2). A plurality of dimple-forming projections (11) are formed on the inner surfaces (2a). At least four tubular gates (7) are disposed in the peripheral surfaces (12) and in fluid communication with the cavity (2). The peripheral surfaces (12) are furrowed except for the areas where the gates are disposed. Dimple-forming pins (14) are received in furrows (13) so as to lie across the parting line (PL). A molten stock material is injected into the cavity (2) through the gates (7) to mold a golf ball having dimples lying across the parting line.

Abstract: An injection molding nozzle is provided that includes a heater disposed about an insert seated in the nozzle body. The heater provides extra heat about the insert where heat loss to the mold can cause a reduction in melt temperature. The heater remains on from one injection cycle to the next injection cycle. In one embodiment, a thermocouple is used to measure the temperature about the insert so that the intensity of the heater can be adjusted accordingly. The heater can also be used with nozzles used in multiple nozzle applications to balance the flow of the nozzles.

Abstract: A foil decorating injection molding machine is provided with an injection mold having a male mold and a female mold. The male mold is provided with a hot runner, a reversing passage connected to the hot runner, and gates connected to the reversing passage and opening into a cavity formed by the male mold and the female mold. The reversing passage has a straight forward feed section connected to the hot runner, a distributing section formed at the downstream end of the forward feed section facing a solid land disposed in the cavity, and reverse feed sections extending from the distributing section to the upstream ends of the gates, respectively, in an obliquely reverse direction at an acute angle to the forward feed section.

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

Abstract: A method of molding golf balls using an injection mold. The golf ball includes a plurality of dimples closely distributed on the surface of the ball. The injection mold for golf balls including a pair of separable mold segments (12, 12) defining a spherical cavity (22) when mated along a parting line (PL). A plurality of hollow tubular gates (20) are disposed in the surfaces of the mold segments to be mated along the parting line and in fluid communication with the cavity. Each gate (20) has a non-circular cross section at its outlet. Opposed portions (20-1, 20-2) of the gate cross section separated by the parting line (PL) have an equal area. A stock material is injected into the cavity through the gates to mold a golf ball.

Abstract: The knit line strength and other packing related properties both aesthetic and functional of injection molded polymeric products is improved by equipping the mold with packing pins. The packing pins are similar in construction to mold ejector pins and may also be mold ejector pins depending on mold configuration. The packing pins are sequentially actuated during or after filling of the mold to cause flow of plastic either transverse or parallel to the direction of flow in a to and from manner. The result is a kneading action in the viscous flow and an oriented layering effect in the solidified plastic much like a scarf joint at the knit line location. The irregular shape of the layers enhances the mechanical strength at the knit line in addition to increasing the likelihood that long chain molecules will re-entangle between the two melt flows at the knit line.

Abstract: In making a toothbrush of the type having a shaft-like handle (3), a neck section (4) joining the handle and a headpiece (5) for toothbrush bristles (6), the body is made of a first plastic material through an injection molding step. In order to provide the body with two or more portions (20, 21, 22) made of a second material, the toothbrush body is provided with recess sections (17, 18, 19). The second material is supplied through a plurality of channels (29, 30, 31, 32) into injection nozzle means (33, 34, 35) to provide injection of the section material in a single step, multi-point injection process into the recesses on the body to form the portions (20, 21, 22), the recesses (17, 18, 19) and the portions (20, 21, 22) thus being physically isolated from each otehr by the first material.

Abstract: A system for injection molding of large components is disclosed that provides for the production of higher quality large molded components with a reduction in both molding cycle time and molding costs. Plasticized material communicates with a mold, having at least one single cavity, through a manifold that has at least two spaced valve gates that are independently opened and closed as directed by a controller to selectively communicate plasticized material to the mold cavity at separate locations in the mold cavity. The controller directs the valve gates to sequentially open and close during the filling phase so as to achieve the desired melt front advancement within the mold cavity. Once the mold cavity has been filled as desired, the valve gates are closed to effectively seal the manifold from the mold cavity.