Valve Pin Hot Runner Nozzle for Edge Gated Injection Molding
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Solution Overview
Problem
Existing edge gating methods in injection molding often result in visible marks on molded parts, which are undesirable for aesthetic or functional reasons, and lack effective control over the material flow.
Innovation Solution
An injection molding apparatus with a hot runner nozzle system that includes a valve pin mechanism for controlling the mold gate, allowing for precise control of the melt stream distribution and eliminating the need for thermal gating, thereby reducing the visibility of marks and improving material flow management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If thermal gating is used to control mold gate opening and closing, then material flow control is achieved, but visible marks are left on the molded parts
Solution Approach 1:
The patent replaces the thermal gating system with a mechanical valve pin system. The valve pin is movable between a retracted position (allowing melt flow) and an extended position (blocking melt flow), providing mechanical control of the mold gate instead of thermal control. This mechanical substitution eliminates the visible marks caused by thermal gating while maintaining precise material flow control.
2Ease of operation
If a movable valve pin is used for mechanical gating, then material flow control is improved, but the complexity of the nozzle system increases
Solution Approach 1:
The patent merges the valve pin mechanism with the existing nozzle structure. The valve pin is integrated into the nozzle body, with its forward end positioned within the nozzle tip. The nozzle includes a valve pin recess that receives and guides the valve pin, combining the gating function with the material delivery function in a single integrated component rather than separate systems.
3Ease of operation
If the valve pin is extended to block the mold gate, then material flow is stopped, but the valve pin tip must be precisely positioned
Solution Approach 1:
The patent introduces a valve pin recess as an intermediary structure between the valve pin and the mold gate. The recess receives the valve pin and provides a controlled environment for its movement. The forward end of the recess positions the valve pin tip at the correct location to effectively block the mold gate when the pin is extended, mediating the positioning requirement and reducing the need for extreme manufacturing precision.
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
The apparatus effectively minimizes the visibility of marks on molded parts and enhances control over the material flow, resulting in improved part quality and functionality.
Implementation Method 1
the valve pin is slidable within the nozzle channel from a first position in which the mold gate is open to a second position in which an outer side surface of the valve pin blocks the mold gate
Implementation Method 2
a plurality of cavities are located in a cooled cavity plate around a heated nozzle
Data Source
AI summary
An edge gated injection molding apparatus includes a manifold having a manifold channel for receiving a melt stream of moldable material under pressure. A nozzle is coupled to the manifold and a nozzle melt channel of the nozzle receives the melt stream from the manifold channel. A mold cavity communicates with the nozzle melt channel of the nozzle and receives melt through a mold gate. The mold gate is located at an edge of the mold cavity. A chamber receives melt from the nozzle channel and communicates with the mold cavity through the mold gate. A portion of the chamber is located forward of the mold gate. A valve pin is slidable through the nozzle channel from a first position in which the mold gate is open to a second position in which an outer side surface of the valve pin blocks the mold gate.