Nitrojection Corporation

Other

Encore Molding Systems, Inc.

Indra R Baxi

Tom W Johnson

Erik E Erikson

Thomas W Johnson

Paul Pardy

Alan Parr

A method for injecting a viscous fluid and a non-viscous fluid into a mold cavity of a mold body includes the step of regulating a flow of viscous fluid through a nozzle body discharge end and into a mold cavity with a valve element. The valve element is mounted for reciprocation in a nozzle body flow passage and includes a barrel having a first end, which selectively engages a portion of the nozzle body discharge end to prevent a flow of viscous fluid therepast, and a second end. A bore extends longitudinally through the barrel and a pin is positioned in the bore. A non-viscous fluid flow passage is defined between the pin and the barrel wherein the non-viscous fluid flow passage is annular in shape and has a substantially constant diameter at and adjacent the barrel first end. A viscous fluid flows through the nozzle body flow passage around the barrel and into the mold cavity. A non-viscous fluid flows through the non-viscous fluid flow passage around the pin and into the mold cavity.

Method for gas assisted injection molding with pin and sleeve mechanism

A method and apparatus for making a plastic injection molded part with a smooth surface or skin and a hollow core wherein thermoplastic material is injected as a molten stream into the mold cavity through a sprue bushing fixed in the mold. Simultaneously, an unmeasured quantity of inert gas is introduced through an adapter into the molten stream at the sprue bushing substantially coaxially with the melt stream and at a pressure sufficient to penetrate the thermoplastic material to form a gas cavity in the molten material in the mold. For retrofitting an existing mold, an adapter can be added to the exisiting sprue bushing. During plastic injection and cooling in the mold the gas is maintained at a high pressure, preset, constant and adequate to maintain the plastic against the mold surface until it is self-supporting. The gas is exhausted from the mold, back through the sprue bushing and adapter, before the mold is opened. Adequate preset high pressure is maintained at the gas supply by a large cylinder having a positive displacement member therein that is controlled by a pressure sensor in the gas pressure line to the mold to maintain preset adequate gas pressure within the cavity.

Injection molding method

Injection molding apparatus

An apparatus for use in gas assisted injection molding of plastic material so as to form an injection molded product includes a pair of mold members defining when closed a sealed cavity. A first opening is provided in one of the mold members for allowing the injection of a plastic material into the cavity. A device is provided to supply a pressurized gas and a second opening is provided in one of the mold members for allowing the injection of the pressurized gas into the cavity. A probe is located in the second opening and is adapted to be reciprocated therein from a retracted position to an extended position. The probe has a first end adapted to selectively extend into the cavity, a second end, and a longitudinally extending bore which terminates in a port located adjacent the first end. The bore is used to guide the gas into the cavity. A device is provided for reciprocating the probe in relation to the cavity. A control system controls the operation of the device for reciprocating as well as the device for supplying a gas.

Apparatus having an in-the-mold gas injection pin

A pressurization control unit for use in a gas assisted injection molding process includes a frame and a gas inflow conduit located on the frame. A gas pressurization device is secured to the frame and is in fluid communication with the gas inflow conduit. A gas storage device is secured to the frame and is in fluid communication with the gas pressurization device. A gas outflow conduit is located on the frame with the gas outflow conduit being in fluid communication with the gas storage device. A valve is provided in the gas outflow conduit for selectively allowing an outflow of the pressurized gas from the gas storage device. A control apparatus is located on the frame for controlling the operation of the gas pressurization device and the valve.

Pressurization control unit for a gas-assisted injection molding machine

An apparatus for injecting a viscous fluid such as a thermoplastic and a non-viscous fluid such as a gas into a mold cavity of a mold body includes a nozzle body having an inlet end, a discharge end and a flow passage for the viscous fluid extending from the inlet end to the discharge end. A valve element is mounted for reciprocation in the nozzle body flow passage to control the flow of the viscous fluid through the nozzle body discharge end. The valve element includes a barrel having a first end selectively engaging a portion of the nozzle body discharge end to prevent a flow of viscous fluid therepast and a second end. A bore extends longitudinally through the barrel. A pin is located in the barrel bore. The pin has a first end located adjacent to the barrel first end and a second end secured to the nozzle body such that the pin remains stationary as the barrel reciprocates in the nozzle body. A non-viscous fluid flow passage is defined between the pin and the barrel.

Plastic injection molding nozzle with gas assist

A process for producing an injection molded product includes introducing a stream of plastic material into a mold space at a first pressure. A quantity of gas is stored in a storage chamber at a second pressure which is at least as high as the first pressure. The gas is introduced into the molten stream of plastic material immediately after the molten material has passed the position at which the gas is introduced thereby forming a gas cavity in the molten material. The gas exerts pressure on the surrounding plastic material to urge the material toward the surfaces of the mold space. As the feeding of the plastic material into the mold space continues, the injection of the gas is also continued. The supply of molten material is terminated when the surfaces of the mold space are completely covered by the molten material. A pressure is held within the gas cavity as the plastic material cools. Subsequently, the pressure is released to bring the mold space to ambient pressure. Then the mold is opened to remove the hollow shaped article. An apparatus for producing an injection molded product is also disclosed.

Process of injection molding with pressurized gas assist

A process for producing an injection molded product includes the step of introducing an amount of a molten thermoplastic sufficient for the preparation of the injection molded product into a mold cavity. A quantity of heated gas is introduced into the mold cavity, the molten thermoplastic in the mold cavity thereby forming a gas cavity in the molten thermoplastic. The heated gas is then vented from the gas cavity and a cooling gas is introduced into the gas cavity. The injection molded product is cooled and then the cooling gas is vented from the gas cavity.

Method for injection molding

A nozzle for injecting viscous fluid such as a thermoplastic into a mold cavity of a mold body includes a tip section and a nozzle body secured thereto. The tip section serves as a sprue of the mold body. The mold body includes a core portion, a cover portion and a clamp plate for securing the core portion to the cover portion. The nozzle body having an inlet end, a discharge end, which communicates with the tip section, and a flow passage for viscous fluid extending from the inlet to the discharge end. A valve element is mounted for reciprocation in the nozzle body flow passage to control the flow of viscous fluid through the nozzle body discharge end. At least the tip section of the nozzle body is located in the mold body cover and the nozzle body is substantially positioned between the mold body cover and the clamp plate. The valve element can be a shut-off needle which is disposed for reciprocating movement in the nozzle body flow passage. A shut-off pin can be disposed for reciprocating movement in the non-viscous fluid flow passage of the shut-off needle to control a flow of fluid through the non-viscous fluid flow passage.

Miniaturized for gas-assisted injection molding

A method and apparatus for making a plastic injection molded part with a smooth surface or skin and a hollow core wherein thermoplastic material is injected as a molten stream into the mold cavity through a sprue bushing fixed in the mold. Simultaneously, an unmeasured quantity of inert gas is introduced through an adapter into the molten stream at the sprue bushing substantially coaxially with the melt stream and ata pressure sufficient to penetrate the thermoplastic material to form a gas cavity in the molten material in the mold. For retrofitting an existing mold, an adapter can be added to the existing sprue bushing. During plastic injection and cooling in the mold the gas is maintained at a high pressure, preset, constant and adequate to maintain the plastic against the mold surface until it is self-supporting. The gas is exhausted from the mold, back through the sprue bushing and adapter, before the mold is opened. Adequate preset high pressure is maintained at the gas supply by a large cylinder having a positive displacement member therein that is controlled by a pressure sensor in the gas pressure line to the mold to maintain preset adequate gas pressure within the cavity.

A bushing used in an injection molding machine and positioned between the nozzle and the sprue thereof includes an adaptor body having a longitudinal axis, a first end and a second end. A first bore extends in the adaptor body parallel to the longitudinal axis from the second end to the first end for accommodating a flow of relatively viscous fluid such as a molten thermoplastic. A bridge extends transversely across the first bore between opposing walls of the bore adjacent the adaptor body first end. Fluid flow is allowed through the first bore around the bridge. A second bore extends from a surface of the adaptor body to a surface of the bridge for accommodating a flow of a relatively non-viscous fluid such as gas. The second bore terminates on the bridge surface so as to be substantially coaxial with the first bore.

Gas supply sprue bushing for injection molding machines

An apparatus for making a plastic injection molded part with a smooth surface or skin and a hollow core wherein thermoplastic material is injected as a molten stream into the mold cavity through a sprue bushing fixed in the mold. Simultaneously, an unmeasured quantity of inert gas is introduced through an adapter into the molten stream at the sprue bushing substantially coaxially with the melt stream and at a pressure sufficient to penetrate the thermoplastic material to form a gas cavity in the molten material in the mold. For retrofitting an existing mold, an adapter can be added to the existing sprue bushing. During plastic injection and cooling in the mold the gas is maintained at a high pressure, preset, constant and adequate to maintain the plastic against the mold surface until it is self-supporting. The gas is exhausted from the mold, back through the sprue bushing and adapter, before the mold is opened. Adequate preset high pressure is maintained at the gas supply by a large cylinder having a positive displacement member therein that is controlled by a pressure sensor in the gas pressure line to the mold to maintain preset adequate gas pressure within the cavity.

Injection molding apparatus for making a hollow object

A process for producing an injection molded product includes introducing a stream of plastic material into a mold space at a first pressure. A quantity of gas is stored in a storage chamber at a second pressure which is at least as high as the first pressure. The gas is introduced into the molten stream of plastic material immediately after the molten material has passed the position at which the gas is introduced thereby forming a gas cavity in the molten material. The gas exerts pressure on the surrounding plastic material to urge the material toward the surfaces of the mold space. As the feeding of the plastic material into the mold space continues, the injection of the gas is also continued. The supply of molten material is terminated when the surfaces of the mold space are completely covered by the molten material. A pressure is held within the gas cavity as the plastic material cools. Subsequently, the pressure is released to bring the gas cavity to ambient pressure. Then the mold is opened to remove the hollow shaped article. An apparatus for producing an injection molded product is also disclosed.

Growing community of inventors

Solon, OH, United States of America

Indra R Baxi