Abstract: A gas assisted molding apparatus having gas introduced into the plastic charge as the charge is flowing into the mold cavity. The gas and plastic are simultaneously injected into the mold cavity and the gas can be introduced at the nozzle end or barrel of the injection molding machine. Optionally, the gas may be injected into a hot runner manifold or into the cavity itself simultaneously with the plastic. The apparatus includes a conventional gas injection mold, a source of inert gas, such as nitrogen, and an injection assembly. A common power source is used for both the injection of the plastic and the gas to assure simultaneous inflow of both the gas and the molten plastic at the same pressure.

Abstract: A gas assisted molding apparatus having gas introduced into the plastic charge as the charge is flowing into the mold cavity. The gas and plastic are simultaneously injected into the mold cavity and the gas can be introduced at the nozzle end or barrel of the injection molding machine. optionally, the gas may be injected into a hot runner manifold or into the cavity itself simultaneously with the plastic. The apparatus includes a conventional gas injection mold, a source of inert gas, such as nitrogen, and an injection assembly. A common power source is used for both the injection of the plastic and the gas to assure simultaneous inflow of both the gas and the molten plastic at the same pressure.

Abstract: A gas assisted molding apparatus having gas introduced into the plastic charge as the charge is flowing into the mold cavity. The gas and plastic are simultaneously injected into the mold cavity and the gas can be introduced at the nozzle end or barrel of the injection molding machine. Optionally, the gas may be injected into a hot runner manifold or into the cavity itself simultaneously with the plastic. The apparatus includes a conventional gas injection mold, a source of inert gas, such as nitrogen, and an injection assembly. A common power source is used for both the injection of the plastic and the gas to assure simultaneous inflow of both the gas and the molten plastic at the same pressure.

Abstract: An injection mold apparatus having two halves, a core portion and a cavity portion. One or more gas injection devices, such as porous metal devices, are located in either of the two portions of the mold. Once a charge of hot melted plastic is injected into the mold cavity, gas is injected through gas injection devices forcing the hot plastic against the opposite mold half and into any recesses and grooves. Gas seals are formed by the plastic to prevent gas in the mold cavity from reaching the exterior surface of the molded part during shrinkage of the plastic. The centers of mass of the plastic at rib intersections are optimally positioned to eliminate sink marks on the external finished surfaces of the molded parts.

Abstract: An injection mold apparatus having two halves, a core portion and a cavity portion. One or more gas injection devices, such as porous metal devices, are located in either of the two portions of the mold. Once a charge of hot melted plastic is injected into the mold cavity, gas is injected through gas injection devices forcing the hot plastic against the opposite mold half and into any recesses and grooves. Gas seals are formed by the plastic to prevent gas in the mold cavity from reaching the exterior surface of the molded part during shrinkage of the plastic. The centers of mass of the plastic at rib intersections are optimally positioned to eliminate sink marks on the external finished surfaces of the molded parts.

Abstract: A mold apparatus and method is used to form a solid injection molded plastic part having no internal voids, a Class A finish, a sink-free exterior appearance surface, and unevenly distributed structural detail extending from the opposite surface, the detail including free-standing reinforcement ribs, attachment bosses, and the like. In sequence, a seal groove in the mold cavity is reduced to a pressure below atmospheric (i.e., negative), a charge of hot thermoplastic is introduced into the mold cavity and seal groove whereby to form a gas seal ring, and pressurized gas is injected into the mold cavity. The pressurized gas forces the hot plastic from one mold half against the other mold half, and the gas seal formed by the plastic prevents gas on one side of the thermoplastic from reaching the appearance surface of the part.

Abstract: A mold bushing for injecting plastic material into a mold cavity. The bushing member has a one-piece body member with a central passageway for a shut-off gate pin member and a separate and distinct passageway for the molten plastic material. In one embodiment, a tip member is positioned on the end of the body member and has a material discharge chamber. A gate or orifice opened and closed by the pin member is positioned either in the tip member or the mold. A wear bushing member can be positioned in the discharge chamber or the end of the body member to support the end of the pin member and prevent the flow of plastic material into the central passageway. The body member is heated by an annular cast heater member or the like. In an alternate embodiment, the body member has an extension which partially fills the discharge chamber and the wear bushing is a cylindrical member positioned at the discharge end of the central passageway.

Abstract: A gas injection pin mechanism for introducing pressurized gas into a mold cavity or melt stream. A stationary pin member is positioned directly in a bore or opening in a mold member without a sleeve member. The pin member is an elongated body member with a first end facing a mold cavity and a first gas passageway through the pin member connected to a second passageway that is traverse to the first gas passageway. The second gas passageway has an opening on an exterior lateral surface of the pin member and gas through the second gas passageway is introduced into the cavity in annular space between the pin member and the mold opening.

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 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 mold bushing for injecting plastic material into a mold cavity. The bushing member has a one-piece body member with a central passageway for a shut-off gate pin member and a separate and distinct passageway for the molten plastic material. A tip member is positioned on the end of the body member and has a material discharge chamber. A gate or orifice opened and closed by the pin member is positioned either in the tip member or the mold. A wear bushing member is positioned in the discharge chamber or the end of the body member and acts to support the end of the pin member and prevent the flow of plastic material into the central passageway. The body member is heated by an annular cast heater member or the like. The wear bushing member can be indexed for proper positioning relative to the body member and the plastic flow passageway. The wear bushing member preferably has a body portion which partially fills the discharge chamber in the tip member.

Abstract: A power factor correction system includes a sensing device in communication with a power supply to measure the line voltage on conventional service lines and detect any voltage fluxuations. A temperature controller receives power from the service lines and supplies an output voltage, based on the line voltage input, to one or more resistive loads, such as heater members. The heater members in turn are used to keep material in a molding device in a molten condition and within a certain temperature range. Fluctuations in the line voltage are detected by the sensing device which prevents corresponding changes in the voltage supplied to the resistive loads from the temperature controller.

Abstract: An injection molding machine [10] for molding plastic parts by injecting a molten plastic through a plurality of valve gates [31] into a mold cavity by reciprocation of a helical screw [16]. A linear position sensor [34] positioned on the machine to detect the position of the helical screw [16] and control the opening and closing of the gates [31] based on the detected position of the screw [16]. A computer is in communication with the valve gates and the position sensor to monitor the position and activate the opening and closing of the valve gates [31]. A pressure transducer is associated with the mold cavity and in communication with the computer [32] as an alternate or additional method for controlling the opening and closing of the valve gates [31].

Abstract: A mold bushing for injecting plastic material into a mold cavity. The bushing member has a one-piece body member with a central passageway for a shut-off gate pin member and a separate and distinct passageway for the molten plastic material. A tip member is positioned on the end of the body member and has a material discharge chamber. A gate or orifice opened and closed by the pin member is positioned either in the tip member or the mold. A wear bushing member is positioned in the discharge chamber or the end of the body member and acts to support the end of the pin member and prevent the flow of plastic material into the central passageway. The body member is heated by an annular cast heater member or the like. The wear bushing member can be indexed for proper positioning relative to the body member and the plastic flow passageway. The wear bushing member preferably has a body portion which partially fills the discharge chamber in the tip member.

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: 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: An electric mold clamping mechanism containing a pair of clamping members is activated by an electric motor. The electric motor operates a threaded piston with acme threads which in turn operate a drive plate to extend and retract the clamping members. The clamping members are used to hold a mold plate in an injection molding machine. The clamping members are pivotally attached to a drive plate mechanism and have a surface which mates with a wedge cam to force the clamping member against the mold plate. The stroke of the clamping mechanism is regulated by an amperage draw on the electric motor. A limit switch is used to terminate the end of the retracting stroke. An indicator light is used to indicate the clamping position of the device.

Abstract: A pneumatic control device for needle valves in injection molding systems. The control device has a control piston, a needle valve, a control cylinder and a cylindrical receptacle in which the control cylinder is positioned. The needle valve is adjustably secured to the piston. The control cylinder has channels for supplying and removal of pressure gas from two cylindrical chambers separated by the control piston. The control cylinder is firmly positioned against the surface of the recess in which it is situated. A plurality of seals positioned between the contact surfaces define two chambers separated from one another. A pressure gas channel is connected to each of the chambers for supply and removal of pressurized gas into and out of the chambers which control the movement of the control piston and thus the needle valve.

Abstract: An electric mold clamping mechanism containing a pair of clamping members is activated by an electric motor. The electric motor operates a threaded piston with acme threads which in turn operate a drive plate to extend and retract the clamping members. The clamping members are used to hold a mold plate in an injection molding machine. The clamping members are pivotally attached to a drive plate mechanism and have a surface which mates with a wedge cam to force the clamping member against the mold plate. The stroke of the clamping mechanism is regulated by an amperage draw on the electric motor. A limit switch is used to terminate the end of the retracting stroke. An indicator light is used to indicate the clamping position of the device.

Abstract: A clamping mechanism for a hot-runner manifold (1) used for injection molding is provided. Screws (11) are used to hold the manifold (1) to a mold plate (7). The screws (11) are attached to clamping members (17) which, in turn, are connected to the manifold. The clamping members (17) include socket portions (21) which are positioned in circular recesses (13) in the manifold. The clamping members (17) can undergo limited pivotal movement due to thermal expansion of the manifold during use.