Co-Injection Nozzle Combining Component for Shear Heating Control
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Solution Overview
Problem
In co-injection molding, hot runner nozzles generate high shear heating and localized shear heating peaks due to annular flow geometry, which are not effectively mitigated by reducing fill flowrate, especially when faster cycle times are desired.
Innovation Solution
A co-injection nozzle design featuring a combining component with inner and outer subcomponents that include apertures and angled grooves to distribute shear-induced heat evenly across the melt streams, reducing shear heating peaks and valleys by redirecting melt streams through a series of apertures and grooves within the nozzle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high fill flowrate is used to achieve faster cycle time, then productivity is improved, but shear heating and localized shear heating peaks increase
Solution Approach 1:
The combining component is divided into multiple subcomponents (inner subcomponent, middle subcomponent, outer subcomponent) with each having multiple apertures. This segmentation distributes the melt flow through numerous smaller pathways, reducing localized shear heating peaks while maintaining overall high flowrate for fast cycle times
Solution Approach 2:
The apertures and grooves create localized flow redistribution zones within the combining component. Each aperture-groove combination acts as a local flow control element that equalizes shear heating in specific regions, achieving a more uniform temperature profile across the entire melt stream
2Device complexity
If conventional annular flow geometry is used, then device complexity is minimized, but localized shear heating peaks occur in multiple areas
Solution Approach 1:
The combining component is divided into multiple subcomponents (inner subcomponent, middle subcomponent, outer subcomponent) with each having multiple apertures. This segmentation distributes the melt flow through numerous smaller pathways, reducing localized shear heating peaks while maintaining overall high flowrate for fast cycle times
Solution Approach 2:
The apertures and grooves create localized flow redistribution zones within the combining component. Each aperture-groove combination acts as a local flow control element that equalizes shear heating in specific regions, achieving a more uniform temperature profile across the entire melt stream
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 achieves a more uniform shear heating profile, reducing temperature variations and pressure drops, leading to improved multi-layer molded articles with reduced shear-induced heat and enhanced process efficiency.
Implementation Method 1
a hot runner co-injection nozzle may generate high levels of shear heating as well as localized shear heating peaks in multiple areas of an annular flow melt stream thereof
Data Source
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AI summary
A co-injection nozzle is disclosed that includes a combining means configured to reduce shear heating and create a more even shear heating profile in core and skin material flow streams. The combining means is configured to reduce shear heating peaks and valleys in core and skin material flow streams as the streams flow between annular channels of the combining means during a mold filling process.