Abstract: A method for injection molding a plastic product having a thin-walled area, includes the steps of(a) injecting molten plastic from a gate into a mold cavity defined by and positioned between a first mold part and a second mold part and encompassed by a parting line, for forming the plastic product; wherein the mold parts define a thin cavity region for forming the thin-walled area of the plastic product, and one or more flow channels which are portions of the mold cavity that are thicker than the thin cavity region;(b) directing the injected molten plastic through the one or more flow channels into the thin cavity region, whereby the molten plastic directed from one portion of a flow channel joins with the molten plastic admitted from the gate or directed from another portion of a flow channel; and(c) melding the molten plastic directed from the one portion of a flow channel with the molten plastic admitted from the gate or directed from the other portion of a flow channel in a meld chamber defined by the mol

Abstract: An injection molding method for controlling the dimensions of a hollow plastic product by using a mold having a first and second mold parts; wherein one of the mold parts includes a retractable portion adjacent a gate. The retractable portion is movable between a protracted position and a retracted position while the mold is closed; and the mold parts define primary flow channels extending from the gate, which, when the retractable portion of the one mold part is protracted, direct initially injected molten plastic from the gate to create stabilizing regions of stiffened plastic. The method includes the steps of (a) protracting the retractable mold part; (b) injecting molten plastic from the gate and through the primary flow channels to create the stabilizing regions; (c) retracting the retractable mold part; (d) subsequently injecting additional molten plastic from the gate between the stabilizing regions into the side wall defining region of the mold cavity.

Abstract: In a mandrel system for receiving a cup-like product having a side wall with a ribbed interior surface, the exterior portion of the mandrel wall is adapted to firmly engage the interior surface of the product side wall in the regions between the ribs and to enhance interior backing of the product side wall in the regions between the ribs. In one embodiment, the exterior portion of the mandrel wall includes a compressible material. In another embodiment, the exterior surface of the mandrel wall includes channels for receiving the ribs on the interior surface of the product side wall. The mandrel wall is apertured to enable air to flow through the mandrel wall to draw the product into firm engagement with the mandrel when a vacuum is created inside the mandrel.

Abstract: A mold for injection molding a plastic product having a thin-walled area includes a first mold part and a second mold part defining a mold cavity therebetween, encompassed by a parting line, for forming the plastic product, and further defining a gate for admitting injected molten plastic into the cavity. The mold parts define a thin cavity region for defining the thin-walled area of the plastic product; and first and second flow channels which are portions of the mold cavity that are thicker than the thin cavity region, for directing the injected molten plastic from the gate into the thin cavity region, whereby the molten plastic directed from the first flow channel joins with the molten plastic directed from the second flow channel.

Abstract: An injection-molded, thin-walled, plastic product is formed by a mold cavity having a thin-cavity region; a pair of flow channels, which are thicker than the thin-cavity region for directing injected plastic into the thin-cavity region; and a meld chamber, which is thicker than the thin cavity region, is displaced from the flow channels, and is at least partially located extensively between the flow channels for melding plastic flowing together from different directions. The product includes a thin-walled area formed by the thin-cavity region; first and second ribs formed by the pair of flow channels, with the first and second ribs being thicker than the thin-walled area; and a third rib formed by the meld chamber, wherein the third rib is displaced from the first and second ribs and is at least partially located extensively between the first and second ribs, with the third rib being thicker than the thin-walled area.

Abstract: In a mold for injection molding and controlling the dimensions of a hollow plastic product having side walls, in which a first mold part and a second mold part define a mold cavity therebetween, encompasssed by a parting line, for forming the hollow plastic product, and further define a gate for admitting molten injected plastic into the cavity; one of the mold parts includes a retractable portion adjacent the gate, with the retractable portion being removable between a protracted position and a retracted position while the mold is closed; and the mold parts define primary flow channels extending from the gate, which, when the retractable portion of the one mold part is protracted, direct initially injected molten plastic from the gate to create stabilizing regions of stiffened plastic, to thereby impede lateral deflection of the mold parts with respect to each other when additional molten plastic subsequently is injected; whereby the side walls of the molded plastic product are uniformly dimensioned.