Pipe Extrusion Die Flow Path Design for Uniform Thickness
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Solution Overview
Problem
Conventional pipe extrusion die designs fail to adequately control material flow properties such as shear rate and shear stress, leading to variations in flow performance, increased production costs due to higher temperatures and pressures, and greater material thickness variations.
Innovation Solution
A pipe extrusion die apparatus with a unique flow passageway design featuring multiple interconnected passageways with varying cross-sectional areas and directions, including conical passageways, to maintain consistent flow properties and optimize material distribution, reducing shear rate and stress variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional extrusion die designs are used with gradually decreasing passage width, then material flows outward toward the extrusion outlet, but material flow properties (shear rate and shear stress) vary substantially causing flow performance variations and material thickness variation
Solution Approach 1:
The flow passage is divided into multiple distinct sections: a first flow passage with substantially constant cross-sectional area for maintaining stable flow properties, and a second flow passage with gradually decreasing cross-sectional area for controlling material distribution. This segmentation allows each section to perform its specific function optimally, resolving the contradiction between flow uniformity and passage design.
Solution Approach 2:
Different sections of the flow passage are designed with different geometric characteristics tailored to their specific functions. The first flow passage has constant cross-sectional area to maintain uniform shear rate and shear stress, while the second flow passage has variable cross-sectional area to control material distribution. This local optimization of passage geometry achieves both flow uniformity and effective material distribution.
2Productivity
If conventional extrusion die designs are used, then material can be extruded through the die, but higher temperatures and pressures are required increasing production costs
Solution Approach 1:
The invention changes the geometric parameters of the flow passage, specifically maintaining a substantially constant cross-sectional area in the first flow passage. This parameter change optimizes the flow characteristics, reducing the energy required for extrusion by minimizing unnecessary pressure builds and temperature increases, thereby improving productivity while reducing energy consumption.
3Reliability
If conventional extrusion die designs are used, then material flows through the die, but substantial changes in flow properties occur causing variations in flow performance
Solution Approach 1:
The flow passage is segmented into a first section with constant cross-sectional area for maintaining consistent flow properties and a second section with variable cross-sectional area for material distribution. This segmentation ensures that shear rate and shear stress remain substantially constant in the first section, improving flow performance consistency while using a relatively simple two-section configuration.
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 improved die design maintains consistent material flow properties along its length, reducing production costs by minimizing temperature and pressure requirements, and achieving more uniform pipe thickness, thus enhancing the efficiency and consistency of the extrusion process.
Implementation Method 1
a conical passageway extending from the second flow passageway toward a dispensing outlet... altering the flow properties of the material
Implementation Method 2
a first flow passageway having a first cross-sectional area and extending along a first flow direction, and a second flow passageway connected to the first flow passageway. The second flow passageway may have a second cross-sectional area substantially the same as the first cross-sectional area and extending along a second flow direction different from the first flow direction
Data Source
AI summary
A method and apparatus is provided for distributing material through a multilayer pipe extrusion die. A first flow passageway, having a first cross-sectional area and extending along a first flow direction, may be connected to a second flow passageway, having a second cross-sectional area substantially the same as the first cross-sectional area of the first flow passageway, to provide a second flow direction different from the first flow direction of the first flow passageway. A conical passageway may extend from the second passageway toward a dispensing outlet. Material may be distributed from the first flow passageway into the second flow passageway. The method and apparatus may generally maintain the same flow properties of the material at a point before and after the connection of the first flow passageway and the second flow passageway. The flow properties of the material may be altered proximate to the outlet.