Abstract: A semiconductor chip mounted on a lead frame is sealed in a synthetic resin package through a molding process, and pressure is applied to synthetic resin softened from granular synthetic resin so as to evacuate the air from the synthetic resin before injecting the synthetic resin into cavities formed in a molding die, thereby preventing the synthetic resin package from void.

Abstract: An apparatus and method utilize vacuum injected molding of a liquid in a plurality of mold cells for solidification therein. An injection head includes spaced apart vacuum and injection slots positionable atop a mold plate in flow communication with the mold cells therein. Relative axial sliding is effected between the injection head and the mold plate for sequentially evacuating gas from the mold cells using a continuous vacuum followed in turn by sequentially injecting into the evacuated mold cells the liquid from a continuous source thereof. Sliding of the injection head over the mold plate automatically provides self valving for sequentially evacuating and filling the mold cells from the same side of the mold plate. In a preferred embodiment, the vacuum and injection slots are linked together at the mold plate so that surface tension of the liquid restrains flow of the liquid from the injection slot to the vacuum slot while allowing gas flow therebetween for effecting the vacuum in the mold cells.

Abstract: A readily replaceable pin-in-sleeve device (A, B) for gas-assisted injection molding is used with a two-part mold to form an injection molded product from a plastic material. A sleeve (10) has a threaded exterior surface that is shaped to be received in a socket (130) of a mold member (210) opening into a mold cavity. A longitudinally extending bore (20) extends through the sleeve. The bore has a first portion (22) adjacent the cavity, and a second, larger diameter portion (24), spaced from the cavity. A pin (40) extends through the sleeve and has a forward section and an enlarged base, which are received in the bore first and second portions, respectively. A tortuous path for an injection fluid is defined between the pin and the bore to inhibit transport of plastic material into the device when the injection fluid is vented from the mold cavity. A filter 60 positioned in the bore, behind the pin, filters traces of plastic material from the vented injection fluid.

Abstract: A method and mold and assembly for use in the mold are provided to make plastic articles having reduced surface defects wherein gases and/or volatiles normally trapped at at least one surface of the article are absorbed by at least one porous part to degas the at least one surface. In one embodiment, first and second porous parts such as porous metal parts can be fit within the first and second mold halves, respectively, to degas opposite surfaces of the article while preventing the passage of plastic from the article-defining cavity in the closed position of the mold. In a second embodiment, a sintered metal plug is utilized to locally degas a single surface of the article. In a third embodiment, an ejector pin and a core pin are formed from sintered metal to degas spaced local surfaces on the same side of the article.

Abstract: A dynamic mold seal for a mold having two relatively movable mold halves is provided. The dynamic mold seal is formed by a sealing ring mounted or secured to a first one of the mold halves. The sealing ring includes a rigid ring portion and a sealing portion including a flexible sealing member for preventing leakage of the pressurized molten material from the mold and thereby preventing the creation of flash about the molded article. The flexible sealing member is preferably formed by a reduced cross section portion of the sealing portion.

Abstract: A mold for use in a gas-assisted injection molding system includes a gas pin assembly which can be readily removed from one mold half in an open position of a mold wherein a porous insert of the assembly can also be readily removed from the housing of the assembly for easy servicing. The housing of the assembly has an elongated aperture formed therethrough in communication with a gas passageway in the mold to permit the flow of gas therethrough. The porous insert is positioned in the aperture. The insert permits the flow of gas therethrough but prevents the passage of molten plastic therethrough. The assembly also includes a holding device preferably in the form of a set screw which has a gas hole formed completely therethrough to permit the flow of gas therethrough. The set screw is threadedly secured within the housing to hold the insert stationary within the aperture and to permit ready removal of the insert from the housing after the set screw has been removed from the housing.

Abstract: A transfer/injection molding apparatus is defined that includes a charge forming unit, a molding unit and a charge overflow unit. The charge is formed so that the fibers therein are randomly oriented in substantially parallel horizontal planes such that they are always substantially parallel to the direction of initial flow into the cavity of the molding unit. Excess charge from the cavity is forced into the charge overflow unit, which is selectively located in an area where surface finish is less critical. The excess charge displaces an overflow pin, which is kept upwardly biased, under molding pressure, to be flush with the lower inside wall of the molding unit cavity.

Abstract: An apparatus and method for assembling a lens-forming structure, the structure having a front mold, a rear mold, and a gasket defining an axially extending bore, including a collet for supporting the gasket so that at least one of the front mold or the rear mold are insertable into the bore thereof, a robotic arm for inserting the front mold into the bore of the gasket, and a piston for inserting the rear mold into the bore of the gasket. The piston axially moves within the bore of the gasket a selected one of the front mold or the rear mold relative to the other mold to a desired one of a plurality of axial separation distances between the molds. Alternatively, the robotic arm can move the selected mold relative to the other mold.

Abstract: A gasket defining an axially extending bore therethrough, a front mold having a an edge circumscribing the front mold, wherein the edge is of a size to be complementarily received within at least a portion of the bore of the gasket so that the edge and the bore form a seal therebetween, and a rear mold having a rim circumscribing the rear mold, wherein the rim is sized to be complementarily received within at least a portion of the bore so that the rim and the bore form a seal therebetween. When the front mold and the rear mold are both disposed within the bore of the gasket, a volume is formed between the back surface of the front mold and the front surface of the rear mold and the interior surface of the gasket. A selected one of the front mold or the rear mold is axially and slidably movable within the bore relative to the other mold disposed within the bore to a desired one of a plurality of axial separation distances between the molds, whereby the volume is different for each separation distance.

Abstract: A fish lure body has integral gussets that hold protruding fins at a predetermined angle to the lure central axis when the lure is moved through water. Molds and methods of molding soft plastic artificial fishing lures in which air is trapped in a blind cavity in a mold and compressed in such a cavity by molten plastic to a pressure that causes the compressed air to eject the finished lure from the mold when the mold is opened after the molten plastic hardens, and artificial fishing lures molded by such methods.

Abstract: A mold for use in a gas-assisted injection molding system includes a gas pin assembly which can be readily removed from one mold half in an open position of a mold wherein a porous insert of the assembly can also be readily removed from the housing of the assembly for easy servicing. The housing of the assembly has an elongated aperture formed therethrough in communication with a gas passageway in the mold to permit the flow of gas therethrough. The porous insert is positioned in the aperture. The insert permits the flow of gas therethrough but prevents the passage of molten plastic therethrough. The assembly also includes a holding device preferably in the form of a set screw which has a gas hole formed completely therethrough to permit the flow of gas therethrough. The set screw is threadedly secured within the housing to hold the insert stationary within the aperture and to permit ready removal of the insert from the housing after the set screw has been removed from the housing.

Abstract: A mold for use in a plastic injection molding system includes a venting pin assembly which can not only vent an article-defining cavity in the mold but can also eject a formed plastic article in an open position of the mold. A porous insert of the assembly permits air from the article-defining cavity to flow there-through while preventing the passage of molten plastic from the article-defining cavity in a closed position of the mold. A venting pin of the assembly in the form of a hollow ejector pin has an elongated aperture formed therethrough to permit the flow of air therethrough. The porous insert is positioned in the aperture at a gas hole formed through an end surface of the ejector pin. The insert and the gas hole are sized so that the insert and the end surface help to form a "Class A" surface on the article formed in the article-defining cavity.

Abstract: A gas injection apparatus for use with a gas assisted injection molding system. The gas injection apparatus includes a mold part defining an elongated bore communicating upstream with a source of gas and downstream with a mold cavity, and an elongated pin positioned in the bore and coacting with the bore to define a gas flow passage therebetween for movement of gas from the gas source to the mold cavity. The bore and pin include first, second and third corresponding portions. The pin and bore define an annular axial clearance in the first portion, a close fit with an axial linear passage in the second portion and an annular axial passage in the third portion. This arrangement ensures that the pin will remain concentric with respect to the bore so as to discourage entry of resin into the annular axial passage.

Abstract: A mold for use in a gas-assisted injection molding system includes an ejector pin subsystem including a split pin which partially blocks the flow of molten plastic through a secondary runner, helps to eject solid plastic from the mold, and helps to define an article-defining cavity and the secondary runner in the mold. A first spill cavity is flow coupled by the secondary runner to the article-defining cavity. The split pin together with other ejector pins are mounted on an ejector plate to move therewith between extended and retracted positions. A second spill cavity is flow coupled by a tertiary runner to the first spill cavity if needed. The split pin, as well as the other ejector pins mounted on the ejector plate, eject plastic from the article-defining cavity, the spill cavities, and the secondary and tertiary runners in the extended position of the ejector plate.

Abstract: A new method and device to encapsulate integrated circuits such as flip chips and BGA packages. A special mold to surrounds the chip to be encapsulated in a cavity, and the encapsulant is injected into the cavity at an elevated pressure, and possibly at an elevated temperature. This shortens the cavity filling time by two or three orders of magnitude, compared to the conventional dispensing process. The reliability of the package is increased by increasing the adhesion of encapsulant to the package, by controlling fillet shape through in-mold curing, and by completely filling the cavity through proper mold design and, optionally, evacuation of the cavity prior to injection. The invention also allows the use of a wider range of encapsulants, including highly viscous material, fast curing materials and reworkable materials.

Abstract: An injection mold system and corresponding method that equalizes pressure of flowable plastic dispensed into an injection mold cavity. A gate in communication with the mold cavity introduces a quantity of flowable plastic into the cavity at a predetermined pressure. A gas inlet in communication with the mold cavity at a mold cavity location remote from the gate introduces a gas into the mold cavity to pack the flowable plastic in the mold cavity at a pressure corresponding generally to the predetermined pressure, to thereby minimize the formation of sink marks and warpage on an injection molded part formed therein. The present invention insures formation of the part with a highly finished appearance surface and eliminates the need for painting or otherwise additional finishing of the part.

Abstract: This invention provides an improved apparatus and method for encapsulating the solder ball interconnections of an integrated circuit assembly which accommodates the use of high viscosity encapsulating materials and enables flush molding to be accomplished without substantially altering the exposed surface of the integrated circuit chip. In accordance with the preferred embodiment of this invention, an integrated circuit chip assembly including an integrated circuit chip mounted on a chip carrier or directly on a circuit board in a standoff relationship by solder ball connections is provided. A mold is placed over the integrated circuit chip. The mold of one embodiment has a compliant material disposed on the molding surface of the mold cavity. The mold also has at least one inlet hole for dispensing encapsulant into the mold, at least one opening for applying a vacuum to the mold and at least one vent.

Abstract: A gas injector including a tube extending into the hollow enclosure of a housing. The hollow enclosure of the housing is connected with gas pressure. The outside end of the tube being extendable into the cavity of a plastic material injection mold. That end of the tube defines a valve seat. A valve is seatable on the seat. A rod on the valve extends through the tube into the hollow enclosure of the housing. A spring in a cup shape support normally urges the rod to move the valve onto the valve seat. A solenoid plunger acting on the rod and activated by an electromagnet moves the rod against the spring to raise the valve off the valve seat.

Abstract: A method and an apparatus for applying a cover sheet of plastic material to the surface of a mold, during the molding of panels and/or of plastic pieces. The cover sheet is pneumatically held and stretched by a support frame provided with a sheet clamping groove, which peripherally extends for at least part or the edges of the mold; the support frame is provided with an air suction chamber connected to the sheet clamping groove by at least an air suction slot which opens on the bottom of the groove. The pneumatic support frame for the cover sheet and the mold are movable between each other for pneumatically adhering the cover sheet to the edges and the internal surface of the mold.

Abstract: A molding apparatus for light-permeable articles which includes a nozzle that is movable up and down. A suction path and a suction device connected to the suction path are provided so as to suck a gas at a contact face of a sprue bush and its vicinity during the up/down movement of the nozzle. Accordingly, foreign substances, invading the mold can be sucked up before the apparatus performs a molding operation. Therefore, foreign substances are prevented from being mixed into the molded product. The molded product is accordingly improved in quality and yield.

Abstract: A fixture for encapsulating microelectronic devices includes a structure defining a device-receiving pocket and a well communicating with the pocket so that the passage and well define an interior space whereby the pocket is disposed above the well when the structure is in a first orientation and the well is disposed above the pocket when the structure is in a second orientation. The fixture also includes an element for sealing the interior space and a port for connecting the sealed interior space to an evacuation device.

Abstract: An apparatus for producing plastic objects with hollow spaces is disclosed. The method has the following steps: establishing a fluid connection (9) between the main cavity (2) of a mold (1) and an overflow cavity (8) and injecting a sufficient amount of plastic melt into the cavity (2) of the mold (1) along a melt flow path, which extends from a plasticizing unit (4, 5) through a plastic injection nozzle (3) into the mold (1), such that plastic melt passes from the main cavity (2) into the overflow cavity (8). The fluidic connection (9) between the main cavity (2) and the overflow cavity (8) is then broken-off prior to the introduction of a pressurized fluid, especially a pressurized gas, into the melt in the cavity (2) by at least one fluid injection nozzle (7), so that the melt situated in the cavity (2) is distributed in the cavity (2) while forming a hollow space, and is pressed against the cavity walls of the mold (1).

Abstract: An automated transfer/injection molding apparatus and process is defined that includes a charge forming unit, a shuttle unit, and a molding unit. The charge is formed from one or more slabs of reinforcing fibers and a resinous material. Once formed, the charge is preheated in the charge shuttle unit and is delivered to the molding unit, whereupon the preheated charges are forced by the pressure of a movable platform under vacuum into a mold cavity for polymerization. The fibers within the slabs are randomly oriented in parallel horizontal planes such that they are always parallel to the direction of initial flow into the cavity.

Abstract: An object of the present invention is to provide a resin molding machine having molding dies, which have simple structures and which can be easily made. Another object is to provide a method of resin molding using release film, which is capable of employing various materials as a material for the molding dies. In the resin molding machine of the present invention, molding dies have molding sections including cavities, and the molding dies are capable of clamping a member to be molded. A pot pressurizes and sends resin melt to the cavities. A fixing mechanism fixes release film, which is capable of easily peeling off from the molding dies and resin for molding, on inner faces of the molding sections and clamping faces, and the fixing mechanism fixes the release film by sucking air.

Abstract: A resin-made vehicular lighting unit having protruding portions is formed in a mold apparatus. The mold apparatus includes first and second molds which are used to form a cavity for resin-molding the vehicular lighting unit. Recessed portions are formed in the first mold and are used to form the protruding portions on a front surface side of the vehicular lighting unit. The second mold includes projecting members, each of which correspond to the recessed portions of the first mold.

Abstract: Apparatus for fluid-assisted injection molding systems or co-injection molding systems. A pair of concentric movable pin members are positioned in a mold bushing and selectively controlled to facilitate or prevent the passage of molten plastic material and a fluid into the mold cavity. An inner pin member is positioned within a hollow pin member and both pin members are controlled by piston members which are selectively moved in a block member by selective pressurization from a hydraulic or pneumatic source. Movements of the piston members selectively controls the operation of the pin members and thus the operation of the fluid-assisted injection molding system.

Abstract: A centrifuge (18) is used to introduce a fluid, particularly a viscous fluid such as an encapsulating resin, into a cavity in a container (10), particularly a small cavity such as the inside of an electronic component housing. Measured quantities of the fluid are placed in dispensing vessels (28) in the centrifuge opposite the containers to be filled. The dispensing vessels have openings (36) through which the fluid can flow when centrifugal force is applied. On the application of this force, all the fluid flows out of the vessels into the containers.

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: In an apparatus for molding resin to seal electronic parts, an internal die space defined at least by pots, cull portions, resin passages and cavities when an upper mold section and a lower mold section are closed, is cut off or sealed from the exterior atmosphere. Thereupon the die space is evacuated using a first evacuation by a vacuum source and a second or instantaneous evacuation by an instantaneous evacuation mechanism. The vacuum source for the first evacuation may be an active vacuum pump, while the instantaneous evacuation mechanism may be a vacuum tank that has been previously pumped down, for example. Using this apparatus, it is possible to quickly improve the degree of vacuum in the internal die space by efficiently and reliably discharging air, moisture and gas from the internal die space to the exterior due to a synergistic action of the evacuation and the instantaneous evacuation. Consequently, the formation of voids in resin molded members is prevented.

Abstract: An apparatus for thermoset molding includes a first mold portion having a first rim and a second mold portion, having a second rim which substantially conforms to the first rim. The first and second mold portions form a mold cavity therebetween. An actuator mechanism is coupled to the first and second mold portions and is adapted to selectively press the first and second mold portions together. An inner seal positioned between the first and second rims and generally conforming to the first and second rims is provided to substantially seal the first and second rims when pressed together. A bridging member spans the inner seal and selectively weakens the inner seal thereby allowing air passage therepast. An injection valve is provided having a plunger which is moveable to allow resin injection or resin blow-through. Further, a mount is provided for removably attaching a clamp to a mold portion.

Abstract: Method and apparatus for manufacturing void free products using vacuum transfer molding. The method comprises evacuating gas from a preheated resin mixture in an injection accumulator assembly before injection into a mold. The apparatus includes a fixed upper platen assembly supporting an injection accumulator assembly having appended thereto a gas exhausting means and a feed material holding canister on its upper surface and an upper match mold portion on its lower surface. The movable lower platen assembly supports a lower match mold portion on its upper surface and is supported by a plurality of hydraulic cylinders of a bottom plate assembly. The platen assemblies include a sandwich of a press plate, an insulating fiber board and an internally heated platen.

Abstract: The invention relates to a method for fabricating hollow plastic objects of thermoplastic material, having the following steps: a) injecting melt into the tool cavity (1, 2); b) Simultaneously and/or subsequently introducing a pressurized fluid into the melt, so that the melt which has been introduced into the molding tool (1, 2) is distributed in the cavity and is pressed against the walls of the molding tool (1, 2), the pressurized fluid being conducted from a pressurized container (5) into the melt, and the pressurized container (5) being supplied with fluid by a compressor (7) which contains a drive element (6); c) allowing the molded part (8) to cool; and d) relieving the cavity of the pressure of the pressurized fluid. According to the invention, the drive element (6) of the compressor (7) is maintained at a temporally constant power level (P) at least over the production of a large number of plastic objects.

Abstract: The present invention is directed to a resilient and self-locking mold for the prototype molding of an object using a liquid resin, the mold comprising first and second mold portions matable to form a mold of the object, the first mold portion having a first opposing mold face with a cavity therein corresponding to the size and shape of the object to be molded, the second mold portion having a second opposing mold face with a core thereon corresponding to the back of the object to be molded, the opposing mold faces of the first mold portion and the second mold portion, upon mating, defining a void therebetween, the void corresponding in size, shape and thickness, to the object to be molded, the void further having a first orifice for providing resin therein, a second orifice for removing air therefrom, the first mold portion and second mold portion further having opposing members of a resilient interlocking pair on the opposing mold faces, the interlocking pair members when interlocked, providing a resilient

Abstract: A compression apparatus which is operated in association with at least two mold parts which can move relative to one another. The compression apparatus is formed of at least one compression units having a working chamber and a working element which can move in it. A gaseous medium can be provided to the working chamber under any initial pressure. During the closing motion of the parts of the mold, the working element is moved in the working chamber, such that the volume in the working chamber is reduced, and in this way, in the course of the closing motion, the gaseous medium is compressed in the working chamber. The compressed gaseous medium can then be sent to a consumer with or without intermediate storage. A compression apparatus of this type is intended for an injection molding machine in which gas pressurization is to take place in a cavity.

Abstract: An apparatus for simultaneously casting a large volume of wax patterns in a reduced amount of time in an air-free environment. The invention utilizes a direct controlled pressure wax injection system to inject melted wax into a central portion of a multi-cavity rubber mold having an upper and lower portion, and then provides an evenly distributed clamping pressure to the mold.

Abstract: A fixture for fixing an annular upper air isolation member which is provided around an outer side of an upper mold section to an upper mounting plate is released, thereby rotating the air isolation member by a rotational member and fixing the same by a rotational position regulating member. An upper chase unit is exchanged through an upper opening which is defined by the upper mounting plate and the rotated air isolation member. A lower chase unit is also exchanged in a similar manner. Due to this structure, a sealing mechanism for a resin sealing/molding apparatus for electronic parts which can readily and quickly exchange a mold in response to small lot production of various types of products is provided.

Abstract: A method is disclosed for the production of a molded article, using a mold assembly including a mold having a cavity, for producing a molded article from a thermoplastic resin; an insert block formed of ceramic or glass having a thermal conductivity of 2.times.10.sup.-2 cal/cm.sec..degree.C. or less, the insert block being disposed inside the mold, constituting part of the cavity, and having a thickness of 0.5 mm to 10 mm; and a cover plate for covering a peripheral portion of the insert block. The cover plate is attached to the mold and constitutes part of the cavity, wherein a clearance between the insert block and the cover plate is 0.001 mm to 0.03 mm, an amount of overlapping of the insert block and the cover plate is at least 0.1 mm. The method includes filling a molten thermoplastic resin in the cavity, and then cooling the thermoplastic resin to solidness.

Abstract: A method of injection molding for use with an injection molding machine includes: a) generating pressurized gas and pressurized moisture within molten plastic as plastic pellets are plasticized in the injection molding machine, the pressurized gas and the pressurized moisture having a total pressure defining an internal counterpressure within the molten plastic; (b) pressuring air within a cavity of a mold in the injection molding machine to an air pressure level which is substantially equal to the internal counterpressure in order to counterbalance the internal counterpressure as the molten plastic is injected into the cavity, thus providing a substantially pressure balanced molding environment for the plastic; and (c) maintaining the air pressure level in the cavity substantially constant as the molten plastic is injected into the cavity.

Abstract: A method and system for injection molding plastic articles which utilize a spill cavity whose volume varies. In one embodiment, the volume varies during introduction of pressurized gas into a mold cavity flow coupled to the spill cavity. In another embodiment, the volume of the spill cavity varies during a plastic injection which fills the mold cavity. A piston reciprocally mounted within a cylinder defines the variable volume of the spill cavity. In one embodiment, a pneumatic control circuit controls the pressure on a lower surface of the piston to thereby control the position of the piston within the cylinder and therefore the volume of the spill cavity. In another embodiment, an air spring is utilized to control pressure on the piston which counters the pressure of the plastic on the piston. In one embodiment, a stop pin connected to the piston prevents the piston from leaving the cylinder when the mold is opened and solidified plastic in the spill cavity is to be ejected therefrom.

Abstract: A method of injection molding for use with an injection molding machine (10) includes: (a) generating pressurized gas and pressurized moisture within molten plastic as plastic pellets are plasticized in the injection molding machine (10), the pressurized gas and the pressurized moisture having a total pressure defining an internal counterpressure within the molten plastic; (b) pressuring air within a cavity (30) of a mold (22) in the injection molding machine (10) to an air pressure level which is substantially equal to the internal counterpressure in order to counterbalance the internal counterpressure as the molten plastic is injected into the cavity (30), thus providing a substantially pressure balanced molding environment for the plastic; and (c) maintaining the air pressure level in the cavity (30) substantially constant as the molten plastic is injected into the cavity (30).

Abstract: An apparatus and method includes a mold which defines a mold cavity with an inlet through which a molten, moldable material can pass into and/or through the mold cavity. A feeder for preparing the molten, moldable material, is spaced from the mold and expels the material to the mold cavity or to an accumulator connected to the mold cavity. A mechanism for controlling the temperature of the material in the feeder, accumulator, and the mold, as well as at least one gas injection unit with controls for the gas before, during and after its injection into the mold cavity and/or into gas channels located within and/or around the mold cavity are provided. A closed loop regulating system easily adjusts and regulates the gas flow and monitors the average gas pressure of the injected gas according to a programmed conditioning signal. The gas injection unit has relief valves and gas tanks.

Abstract: A method and apparatus for resin transfer molding composite materials that emit volatiles. The apparatus includes an RTM tool, a constant displacement injection pump, a heater connected to a power supply, one or more porous tool inserts, and one or more articulated tool inserts. The porous tool inserts are mounted within the RTM tool and allow volatiles produced during processing to flow through the inserts. The volatiles are drawn through the porous tool inserts and out through an exhaust port. The articulated tools are also mounted within the interior of the RTM tool. The articulated tools are movable in order to increase and decrease the volume of the RTM tool. As volatiles are emitted, the articulated tools are moved in order to decrease the volume of the tool. The articulate tools are also used to apply a consolidation force to the resin and fiber-reinforced preform within the tool.

Abstract: A device for the production of a green from slurry by solidification after injection into a mold having a temperature of less than 0.degree. C. The device includes a mold having a jack wherein moveable parts of the jack ensure closure thereof and which are housed within a gas-tight vessel. A distributor for dry gas with a dew point lower then the temperature of the mold emits a gas current into the vessel through apertures. A chute conducts the green towards an exit aperture and to a receiving member outside the vessel.

Abstract: A molding method is used to mold a semiconductor device within a molded carrier ring. A mold tool (30) has an upper platen (32) and a lower platen (34). Each platen has a package cavity (36) and a carrier ring cavity (38). Between the package and ring cavities is a venting hole (60) having a venting pin (63) slidably fit therein. The venting pin includes a flat surface (64) that allows air which is forced from the package cavity during molding to escape through a narrow gap. The gap size is made small enough to prevent the passage of resin to flow through. Thus, the invention permits the mold tool to be compression cleaned and prevents mold tool down-time previously experienced when molding resin gets dogged in traditional venting holes. In another embodiment, the venting pin can be placed within the package cavity and also serve as an ejector pin.

Abstract: A method of injection molding for use with an injection molding machine includes: (a) generating pressurized gas and pressurized moisture within molten plastic as plastic pellets are plasticized in the injection molding machine, the pressurized gas and the pressurized moisture having a total pressure defining an internal counterpressure within the molten plastic; (b) pressuring air within a cavity of a mold in the injection molding machine to an air pressure level which is substantially equal to the internal counterpressure in order to counterbalance the internal counterpressure as the molten plastic is injected into the cavity, thus providing a substantially pressure balanced molding environment for the plastic; and (c) maintaining the air pressure level in the cavity substantially constant as the molten plastic is injected into the cavity.

Abstract: A plastic molding method for semiconductor devices, the method including placing semiconductor devices mounted on lead-frames between lower die cavities in a lower die chase block and upper die cavities in an upper die chase block and clamping the upper and lower die chase blocks together; evacuating an ejector chamber in the lower die chase block through a lower die common surface table, evacuating an ejector chamber in the upper die chase block through an upper die common surface table, and evacuating a parting chamber at a parting surface between the lower die chase block and the upper die chase block through one of the lower die common surface table and the upper die common surface table; and injecting a sealing resin into the upper die cavities and the lower die cavities to plastically package the semiconductor devices.

Abstract: An injection molding apparatus for a resin structure uses gas injection. The apparatus includes a resin supply that feeds more than one resin to a mold, a gas exhaust that discharges gas supplied to the resin in order to closely contact the resin to the mold, and a supply selector that selectively opens and closes the resin supply using the pressure of the discharged gas to supply a different kind of resin onto the inner surface of a previously supplied resin.

Abstract: A mold for encapsulating a transformer coil assembly in thermoplastic rubber includes a bottom mold portion having a mold cavity, an upstanding pin disposed within the mold cavity, a mold cover for closing the mold cavity, and a vent space positioned in the bottom surface of the mold cavity for venting gas within the mold cavity to the exterior of the mold during the injection of thermoplastic rubber into the mold cavity.

Abstract: Provided is a method of making a multi-property polyurethane part by RIM having a surface layer and an interior layer. The surface layer and the interior layer have different properties. The pressure in the cavity of the mold is reduced and a surface forming RIM polyurethane material is injected into the evacuated cavity, whereby the surface layer of the molded part is formed by RIM. An interior forming RIM polyurethane material is injected into the evacuated cavity, whereby the interior of the molded part is also formed by RIM.

Abstract: A mold for producing foamed articles includes an upper mold and a lower mold which define a mold cavity. A vent is provided in communication with the mold cavity and has a vent passageway with an entrance and an exit. Structure is also provided for sealingly engaging the upper mold with the lower mold to cause, in cooperation with the predetermined size and shape of the vent passageway, liquid foam polymeric composition expanding inside the mold cavity to enter the vent entrance but to not exit from the vent exit to cause at least partial curing of the foam composition within the vent passageway. Preferably, the vent may be ribbon-shaped so that a ribbon of foamed composition adheres to the foamed article and may be folded flat against the article thus avoiding the labor step of trimming the flash from the product. Additionally, .[.or alternatively,.].