Multi-Member Guillotine Valve for Uniform Injection Mold Flow
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Solution Overview
Problem
Existing injection molding technologies face issues with flow disturbances and defects due to the use of linearly movable stems or single guillotine valves, leading to material accumulation, stagnation, and thermal inconsistencies, which result in waste and product defects.
Innovation Solution
An obturation valve with multiple obliquely mounted obturating members that converge to a common point, allowing for a compact, robust, and thermally stable structure that minimizes material compression and ensures uniform flow control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single movable guillotine valve is used to control material flow, then the device complexity is reduced and space is saved, but the material is squashed towards the nozzle perimeter causing defects in the molded product
Solution Approach 1:
The single guillotine valve is divided into multiple obturating members (at least two) that operate independently. Each member can be positioned to control material flow without forcing material toward the nozzle perimeter, thereby maintaining product quality while retaining structural simplicity.
Solution Approach 2:
Different regions of the valve are designed with different properties: the obturating members are positioned at specific locations (e.g., center or offset from center) to create localized control zones. This allows material to close at optimal positions without peripheral compression, solving the quality issue while keeping the overall device simple.
2Adaptability or versatility
If the nozzle is positioned on the mold surface along a non-perpendicular axis to reduce space, then the adaptability is improved, but the pressure forces from injected material cause bending and stress concentrations that may induce fractures
Solution Approach 1:
The valve structure is designed to accommodate non-perpendicular nozzle positioning by introducing angular degrees of freedom. The obturating members can move along inclined axes rather than strictly perpendicular to the nozzle, allowing the nozzle to be positioned at various angles without compromising mold strength.
Solution Approach 2:
The valve geometry is made asymmetric to match the non-perpendicular nozzle configuration. The obturating members are positioned and oriented to work effectively at angled positions, distributing stress more evenly and preventing concentration at specific weak points in the mold die.
3Temperature
If two opposing planar guillotines are used with closing point at the center of the channel, then the thermal conditions are improved (higher temperature), but the actuation mechanism becomes complex with considerable complications and imprecise control
Solution Approach 1:
The complex actuation mechanism is segmented into multiple independent actuators, each controlling a single obturating member. This simplifies the control of each individual component while maintaining the overall center-closing function, achieving precise control through modular simplicity.
Solution Approach 2:
Instead of using a single complex actuator to control multiple guillotines simultaneously, the approach is inverted: multiple simple actuators each control one obturating member independently. This achieves the same center-closing effect with simpler, more controllable individual components.
Data Source
AI summary
An obturation valve is described for controlling a flow of molten material exiting from a nozzle into a mold cavity, comprising a channel for the molten material extending along a first axis, two or more obturating members that are mounted movably along a respective second axis inclined at an acute angle with respect to the first axis and so that a free end of each obturating member can move and converge towards the same point inside the channel. The free ends of the obturating members can join at said point to compose a blocking/closing bulkhead for the molten material.