Extruded Tube Wall-Thickness Profiling for Melt Sagging Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods struggle to precisely detect and control the sagging of melt in extruded tubes during the cooling process, which affects the wall thickness distribution and shape accuracy.
Innovation Solution
Measure the wall thickness of the tube over its circumference to produce a wall-thickness profile, and determine sagging by analyzing the frequency and amplitude modulation of this profile using terahertz radiation, allowing for precise detection and control of sagging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the tube is measured shortly after exiting the extrusion device, then the geometric parameters can be determined, but the determined parameters deviate from the actual parameters in the completely solidified state due to sagging
Solution Approach 1:
The patent uses wall thickness measurements taken during the cooling process as feedback to determine sagging magnitude. This feedback information is then used to calculate compensation values that correct the geometric parameters, allowing accurate determination of final dimensions even when measured during the cooling phase before complete solidification.
2Manufacturing precision
If setting elements are provided on the extruder nozzle to set wall thickness at multiple points, then wall thickness distribution can be controlled, but the complexity of the extrusion device increases
Solution Approach 1:
The patent replaces complex mechanical setting elements on the extruder nozzle with a measurement and calculation system. Instead of using mechanical means to physically adjust wall thickness distribution, the system measures actual wall thickness during cooling, determines sagging from these measurements, and calculates the required geometric parameters mathematically, thereby reducing mechanical complexity.
3Productivity
If the melt temperature is increased to improve output capacity, then productivity increases, but the risk of uncontrolled sagging and shape deviation increases
Solution Approach 1:
The patent implements a feedback system where wall thickness measurements during cooling provide information about actual sagging that occurred at higher temperatures. This feedback allows the system to calculate and compensate for shape deviations, enabling safe operation at higher melt temperatures for improved productivity while maintaining shape accuracy through post-measurement correction.
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
Enables simpler and more precise detection of sagging, facilitating stable production processes and shape control of extruded tubes by adjusting process parameters based on the detected sagging.
Implementation Method 1
a precise determination of geometric parameters, such as diameter or wall thickness of tubes extruded in an extrusion device, is possible
Implementation Method 2
during the solidification of extruded tubes, downward sagging of the melt as a result of gravity regularly occurs
Data Source
AI summary
A method for determining sagging of melt of a tube extruded in an extrusion device includes structuring a measuring device to rotate about the tube. The measuring device is configured to measure a wall thickness of the tube over a circumference of the tube and determine a wall-thickness profile over the circumference of the tube from the measured wall thicknesses. The wall-thickness profile includes a frequency and an amplitude. The method further includes determining a sagging of the melt from at least one of (i) the frequency and (ii) the amplitude of the wall-thickness profile.