Extrusion Foam Layer Measurement Using THz and Feed Data
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Solution Overview
Problem
Existing methods for determining layer properties in extrusion processes, particularly for mixed layers like foam layers, are inadequate due to insufficient electro-magnetic measurements and unknown refraction indices, making it difficult to accurately measure layer thickness and material composition during the extrusion of products like foamed plastics and fiber-reinforced materials.
Innovation Solution
Combining electro-magnetic measurements, such as Terahertz radiation, with gravimetric and volumetric data from the material feed to determine the refraction index and foaming ratio of mixed layers, allowing for real-time regulation of the extrusion process by adjusting the material feed based on measured layer properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasound measurements are used to determine wall thickness, then measurements can be performed on extrusion products, but measurements become difficult with mixed layers like foam layers due to strong reflection, attenuation, and diffusion of different components
Solution Approach 1:
The patent introduces Terahertz radiation as an intermediary measuring agent that can penetrate foam layers and mixed materials without being strongly reflected, attenuated, or diffused like ultrasound. The Terahertz radiation serves as a mediator between the measurement system and the mixed layer, enabling accurate thickness and property determination through the complex material structure.
Solution Approach 2:
The patent changes the physical parameter of the measurement radiation from acoustic waves (ultrasound) to electromagnetic waves in the Terahertz range. This parameter change allows the measurement to penetrate mixed layers effectively, as Terahertz radiation interacts differently with foam and composite materials compared to ultrasound, reducing reflection and attenuation effects.
2Measurement precision
If Terahertz radiation is used for wall thickness measurements, then measurements can be performed, but foam layers cannot be measured because the refraction index is undetermined due to unknown composition
Solution Approach 1:
The patent implements a feedback mechanism where the measured Terahertz signal characteristics (transmission, reflection, absorption) are used to iteratively determine the refraction index of the foam layer. The system adjusts its understanding of the material properties based on the measured response, allowing accurate thickness determination even when the initial composition is unknown.
Solution Approach 2:
The patent performs preliminary characterization of the foam layer by measuring multiple Terahertz signal parameters (transmission coefficient, reflection coefficient, absorption characteristics) before calculating the final thickness. These preliminary measurements provide the necessary information about refraction index and material composition that are then used in the thickness calculation.
3Measurement precision
If electro-magnetic measurements are performed on mixed layers, then layer properties can be determined, but the unknown refraction index prevents accurate evaluation of foam layer properties
Solution Approach 1:
The patent moves the measurement from a single-parameter approach (assuming known refraction index) to a multi-dimensional measurement space that captures transmission, reflection, and absorption characteristics. By measuring in multiple dimensions, the system can simultaneously determine both the refraction index and layer thickness, making the measurement reliable even when material properties are initially unknown.
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 fast, complex-free, and energy-efficient in-line measurements of extrusion products, allowing for immediate process corrections and improved quality control by determining layer properties like refraction index and thickness, applicable to various extruded products including foamed and fiber-reinforced materials.
Implementation Method 1
measuring by means of an electro-magnetic measuring procedure, in particular, a THz measuring procedure
Implementation Method 2
determine a refraction index of the at least one mixed layer
Data Source
AI summary
Method for determining at least one layer property of a layer to be determined, in particular a foam layer, in an extrusion process, where a supply material is at least partially foamed and an extrusion product with the foam layer is put out (in other words, is output). The method has at least the steps of irradiating the extrusion product using electro-magnetic radiation, and electro-magnetically measuring at least one radiation having travelled through the foam layer. Measuring at least one feed-in rate or feed-in volume of the supply material, and determining the at least one material property of the layer to be determined from the measured feed-in volume and the electro-magnetic measurement.