Injection molding nozzle structured for cooling at extreme tip
AssigneeThermal Wave Molding Corp.
InventorsFrank J. Baresich, Robert F. Thompson
Life of this patent
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Abstract
A nozzle for injection molding is made of at thermally conductive metal material but is thermally conductively blocked or interrupted. An abrupt reduction in wall thickness and/or a gap in the continuity of thermally conductive material occur along the nozzle material passageway. This provides a localized restriction to thermal conduction, causing a reduction in heat flow from the mold to the material supply while cooling the melt material near the end of the nozzle. This material, which is relatively cooled to near the mold temperature, becomes the last injected material when filling of the mold is completed, occupying the area of the sprue. As a result, the sprue is relatively cool, thus reducing stringing and shortening mold cycle time.
Claims14
A nozzle for injection molding, comprising:
- a thermally conductive nozzle body defining an internal passage for conveying a flow of heated melt through the nozzle body, wherein the internal passage extends axially along the nozzle body to an axially placed cylindrical hub of a diameter less than a diameter of the nozzle body;
- a tubular extension from the cylindrical hub, the tubular extension having a wall thickness less than a wall thickness of the cylindrical hub;
- a nozzle tip on an end of the nozzle body, communicating with the internal passage, wherein the nozzle tip is structured for engagement with a mold for coupling the passage to an injection inlet;
- and,
- wherein a heat flow blocking configuration is disposed between an extreme end of the nozzle tip and a point of the internal passage spaced back from the nozzle tip.
A nozzle for injection molding, comprising:
- a thermally conductive nozzle body defining an internal passage for conveying a flow of heated melt through the nozzle body;
- a nozzle tip on an end of the nozzle body, communicating with the internal passage, wherein the nozzle tip is structured for engagement with a mold for coupling the passage to an injection inlet;
- a heat flow blocking configuration disposed between an extreme end of the nozzle tip and a point of the internal passage spaced back from the nozzle tip, the heat flow blocking configuration comprising a portion having reduced thermal conduction capacity between the extreme end and the point spaced back from the nozzle tip, said portion including a reduced wall thickness along the internal passage, and a material gap extending radially over an axial span between the extreme end and the point of the internal passage spaced back from the nozzle tip.
Dependencies are inferred from the claim text.