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US 2002/0163106 A1Published application
Fluid compression of injection molded plastic materials
AssigneeIncoe Corporation
InventorJames W. Hendry
Life of this patent
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AssigneeIncoe Corporation
InventorJames W. Hendry
Estimating the term…
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.
A plastic molding apparatus including closable first and second mold members defining a mold cavity, means for injecting a predetermined quantity of molten plastic material into said mold cavity, and means for applying external gas pressure along the backside surface of the plastic material which forces the plastic material away from the surface of the mold cavity adjacent said backside surface and against the opposite surface of the mold cavity, the plastic material is self supporting, the plastic material forming a molded product with a wall member and at least one elongated rib member along said backside surface of said wall member, the improvement comprising the width of the rib member being less than forty percent larger than the width of said wall member, and the intersections of said rib member and the wall member having fillets or radii less than 1.0 mm in radii.
A method of injection molding a plastic product having a first wall member with an outer appearance surface and a backside surface and a first reinforcing rib member positioned on said backside surface, the method comprising the steps of:
A plastic molding apparatus including closable first and second mold members defining a mold cavity, means for injecting a predetermined quantity of molten plastic material into said mold cavity, and gas pin members for injecting pressurized gas and applying external pressure on one surface of the plastic material to force the plastic material away from the surface of the mold cavity adjacent thereto and for maintaining the external pressure until the plastic material is self supporting, the improvement comprising:
Dependencies are inferred from the claim text.