Injection Molding Nozzle With Branching Flow Passages
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Solution Overview
Problem
Existing injection molding systems face issues with poor flow of molten materials due to shear caused by valve pins and uneven heat transfer, leading to degraded material quality and control over the molding process.
Innovation Solution
A nozzle and drop tip assembly with branching flow passages and a valve gate assembly that allows independent flow of molten materials, with the valve member isolated from the flowing material and heat sources positioned for even heating, ensuring consistent pressure and improved flow control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a valve pin is positioned within a flow passageway to regulate molten material flow, then flow control is achieved, but shear on the molten material increases and flow quality degrades
Solution Approach 1:
The invention removes the valve pin from the interior of the flow passageway and relocates it to the exterior surface of the nozzle. The pin contacts the molten material only at the gate opening, not within the flow passageway. This extraction eliminates the harmful shear effect on the flowing material while preserving the valve pin's flow control function.
2Ease of manufacture
If flow passageways are positioned asymmetrically relative to heat sources, then manufacturing is simplified, but heat transfer to molten materials becomes uneven
Solution Approach 1:
The invention deliberately positions the flow passageways asymmetrically relative to each other, with first and second passageways located at different radial distances from the central axis. This asymmetric arrangement is specifically designed to create equal path lengths from each passageway to its respective heat source, ensuring uniform heat transfer despite the asymmetric geometry.
3Adaptability or versatility
If multiple materials are injected sequentially through a single gate, then multi-material parts are produced, but pressure variations and flow control issues occur
Solution Approach 1:
The invention divides the single gate into multiple separate gates, with each material having its own dedicated flow passageway and gate opening. This segmentation allows independent pressure control and flow regulation for each material, eliminating pressure variations that would occur with sequential injection through a shared gate.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances the flow of molten materials, reducing shear and pressure variations, resulting in improved material quality and appearance of molded parts with greater control over the injection molding process.
Implementation Method 1
The injection molding system often includes one or more heat sources, such as heating bands positioned on the outer surface of the nozzle and the manifold assembly. The heat sources supply heat to the molten material to maintain desired flow conditions.
Data Source
AI summary
An injection molding system for injection molding a plurality of molten materials into a mold cavity includes a nozzle, a drop tip supported by the nozzle, and a central bore extending through the nozzle and drop tip. The injection molding system also includes a first and second flow passage each extending through the nozzle, so as to define a first and second nozzle flow passage, and drop tip, so as to define a first and second drop tip flow passage. The first and second drop tip flow passages each include a plurality of branching portions each defining a junction at which the respective flow passage communicates fluidly with the central bore.