Extrusion Die Heating Part Reduces Stress Gradients
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Solution Overview
Problem
Sheet extrusion dies face issues with unstable sheet formation due to high stress and stress gradients at the outlet, leading to tilting and waving, which affect subsequent processing steps.
Innovation Solution
An extrusion die design with a storage part, pressure part, first die, and second die, where the flow width narrows and then widens, combined with a heating part that raises the temperature of the raw material by 5 to 20°C, minimizing stress and stress gradients by applying heat across the entire flow width, particularly near the outlet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the raw material passes through the sheet die with a sharp stress gradient, then the extrusion process can be completed, but the sheet becomes unstable, tilted, and wavy at the outlet
Solution Approach 1:
The patent applies parameter changes by introducing a heating part that raises the temperature of the raw material by 5 to 20°C as it passes through the second die. This temperature parameter change reduces the stress magnitude and stress gradient, thereby stabilizing the sheet formation at the outlet and eliminating tilting and waviness while maintaining extrusion productivity
Solution Approach 2:
The heating part is strategically positioned to apply heat locally to the raw material in the region where high stress and stress gradients occur (near the outlet of the second die). This localized heating approach specifically addresses the stability issue at the outlet without affecting other parts of the extrusion process
2Force
If the flow width is reduced in the first die, then the raw material is compressed effectively, but the stress magnitude and stress gradient increase significantly
Solution Approach 1:
The heating part compensates for the increased stress magnitude and stress gradient caused by the width reduction in the first die by raising the temperature of the raw material. This thermal parameter change reduces the stress effects, allowing effective compression while minimizing harmful stress concentrations
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 temperature increase reduces stress magnitude and stress gradients, improving sheet stability and reducing tilting and waving, with stress gradients being halved at a 10°C temperature rise.
Implementation Method 1
a heating part configured to heat the raw material passing through the second die
Data Source
AI summary
The present invention relates to an extrusion die and a method for extruding a sheet using the same, and according to one aspect of the present invention, there is provided an extrusion die comprising a storage part configured to hold a raw material, the storage part defining a first width, a pressure part configured to move the raw material through the storage part, a first die defining a second width less than the first width, such that a flow width of the raw material becomes narrower, a second die in fluid communication with the first die, the second die defining a width that increases from the second width to a third width, such that the flow width of the raw material passing through the first die becomes wider and a flow thickness becomes smaller, and a heating part configured to heat the raw material passing through the second die.