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US 5,118,455 AGranted
Gas assisted injection molding
OwnerNorman S. Loreninventor
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OwnerNorman S. Loreninventor
Estimating the term…
A method and apparatus for providing gas assistance in a resin injection molding process of the type in which hot resin is injected into a mold, gas is injected into the mold to displace a portion of the resin in the mold, the resin cools, the gas is vented, and the mold is opened to remove the molded part. The apparatus includes a high pressure gas storage system, a plurality of pressure control assemblies set at varying pressures and interposed between the high pressure gas storage system and the injection nozzle, and a control system which is operative to selectively communicate each of the pressure control assemblies with the injection nozzle so as to allow the delivery of gas at varying pressures to the mold to facilitate the creation of an individualized gas pressure profile to suit the particular molding requirement. The apparatus further includes a supplemental gas storage system including a plurality of gas storage containers interposed between the pressure control assemblies and the injection nozzle so that the supplemental gas storage system may be used in selective cooperation with the pressure control assemblies to provide further versatility with respect to the ability to tailor the pressure profile to the particular molding requirement.
A method of providing gas assistance to a resin injection molding process of the type in which hot resin is injected into a mold cavity and gas is injected into the resin to displace the resin in the mold cavity, means are provided to selectively control the pressure of the gas in the mold, the gas is stored at a first storage pressure as determined by the control means, the gas at the first storage pressure is reduced to a second lower pressure as determined by said control means, and the gas is injected into the mold at said second lower pressure to displace the resin in the mold cavity, the resin cools, the gas is vented, and the mold is opened to remove the molded part, the improvement wherein following the injection of the gas into the mold at said second lower pressure the gas pressure in the mold is increased to a third pressure as determined by said control means.
A method of providing gas assistance to a resin injection molding process of the type in which hot resin is injected into a mold, gas is injected into the mold to displace a portion of the resin in the mold, the resin cools, the gas is vented and the mold is opened to remove the molded part, a supply of stored as is provided, the gas is injected into the mold to displace the resin in the mold cavity at a pressure that is at all times during the gas injection cycle substantially below the pressure of the stored gas supply, the improvement wherein, following the initial injection of the gas into the mold and prior to the venting of the gas from the mold, the gas pressure within the mold is selectively increased, decreased, or held substantially constant depending upon the particular requirements of the molding process.
An apparatus for providing gas assistance to a resin injection molding process of the type in which hot resin is injected into a mold cavity, gas is injected into the mold to displace a portion of the resin in the mold, the resin cools, the gas is vented and the mold is opened to remove the molded part, the improvement wherein a supply of stored gas is provided and the apparatus includes control means which are operative to inject gas into the mold to fill out the mold cavity at a pressure that is at all times during the gas injection cycle substantially below the pressure of the stored gas supply and which are further operative, following the initial injection of gas into the mold and prior to the venting of the gas from the mold, to selectively increase the gas pressure within the mold, decrease the gas pressure within the mold, or maintain the gas pressure within the mold at a particular value.
An apparatus for providing gas assistance in a resin injection molding process of the type in which hot resin is injected into a mold, gas is injected into the mold to displace a portion of the resin in the mold, the resin cools in the mold, the gas is vented from the mold, and the mold is opened to remove the molded part, the improvement wherein the apparatus includes control means which are operative to store the gas at a first high pressure, to reduce the first storage pressure to a second lower pressure, to inject the gas into the mold at the second lower pressure, and to thereafter increase the gas pressure within the mold to a third pressure.
A gas assisted injection molding apparatus for use with an injection mold, said apparatus comprising:
A gas assisted injection molding apparatus for use with an injection mold, said apparatus comprising:
Dependencies are inferred from the claim text.