Melt spinning nozzle tip
OwnerJobst U. Gellertinventor
Life of this patent
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Abstract
This invention relates to an improved valve-gated injection molding system. The hot runner passage through which the melt flows to the cavity is divided into three spiral-shaped channels which converge again immediately before the gate, thereby imparting a curving motion to the melt as it flows outward from the gate in the cavity. This avoids unidirectional molecular orientation of the melt, thereby providing a stronger molded product. In a preferred embodiment of the invention, the melt channels reduce in helical diameter and cross sectional area as they approach the gate, thereby accelerating the swirling motion of the melt.
Claims7
In a valve-gated injection molding system comprising a gate in a cavity plate leading to a cavity, a molding machine, a hot runner passage extending through a heated heater cast for conveying pressurized plastic melt from the molding machine to the gate, an elongated valve pin to reciprocate in a generally cylindrical bore in the heater cast between open and closed positions, the valve pin having a driven end and a tip end which is received in the gate in the closed position, and valve pin actuating mechanism, the improvement wherein at least a portion of the hot runner passage immediately preceding the gate is divided into a plurality of separate channels which converge again adjacent the gate, each channel being spiral shaped with the valve pin extending centrally therethrough,
- whereby a curving motion is imparted to the melt when it enters the cavity through the open gate thereby reducing unidirectional molecular orientation of the melt.
Dependencies are inferred from the claim text.