Laser Transmission Scanning for EPS Density Mapping

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Solution Overview

Problem

Current methods for testing the density and homogeneity of components, particularly in expandable plastics, are labor-intensive and only allow for overall density determination, requiring destructive sampling and significant effort.

Innovation Solution

A non-destructive testing method using two-dimensional scanning with a laser beam to record spatially resolved transmission images of components translucent to infrared, visible, or ultraviolet light, allowing for spatially resolved density and homogeneity analysis, which can be integrated into manufacturing processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If destructive sampling with buoyancy method is used for local density determination, then density measurement is possible, but testing effort and time increase significantly

Engineering Contradiction:
Improvelocal density determinationVSAvoidtesting effort and time
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces the mechanical destructive sampling method (cutting components into segments and using buoyancy method) with an optical measurement system. A laser beam scans through the component, and a detector measures light transmission intensity. The system uses optical fields instead of mechanical cutting and water displacement to achieve density measurement, enabling non-destructive, rapid, and spatially resolved density determination throughout the component.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If overall density determination by volume and mass measurement is used, then testing is simple, but spatially resolved density information is lost

Engineering Contradiction:
Improvetesting simplicityVSAvoidspatially resolved density information
Core Design Contradiction:
Ease of manufactureVSLoss of information

Solution Approach 1:

The patent applies segmentation by dividing the component into numerous small measurement points along the laser scan path. The laser beam scans through different locations (x, y coordinates) of the component, and the detector records transmission intensity at each point. This creates a spatially resolved density map that shows density variations throughout the component, maintaining measurement simplicity while gaining detailed spatial information.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If laser beam scanning is used for spatially resolved density measurement, then non-destructive testing with spatial resolution is achieved, but scattered light reduces measurement accuracy

Engineering Contradiction:
Improvespatially resolved density measurementVSAvoidscattered light interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a spatial filter as an intermediary element between the component and the detector. This spatial filter selectively transmits only the laser beam that has passed through the component while blocking scattered light. The filter acts as a mediator that separates the useful transmitted light from harmful scattered light, thereby improving measurement accuracy in spatially resolved density measurements.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 rapid, cost-effective, and non-destructive testing of components with low densities, providing direct process control and quality assurance, reducing testing effort and time, and allowing for analysis of complex geometries and density fluctuations.

Implementation Method 1

a spatially resolved transmission image of the component, the area or the volume is recorded by two-dimensional scanning of the component, the area or the volume with a laser beam for which the component, the area or the volume is translucent... by measuring the intensity of the laser beam that has passed through the component or volume and is thus weakened

Methodology Applied
Scientific EffectLight transmission and absorption: Absorption (EM radiation)

Data Source

PatentEP2108939B1Method for inspecting the density and/or homogeneity of structural components
Publication Date: 2013.11.06 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP2108939B1 patent drawingFigure 1~2

AI summary

The method involves capturing a space-resolved transmission image of an expandable polystyrene component (3), an area of the component, or volume that is completely translucent or translucent in a region of electromagnetic radiation, by two-dimensional radiation of the component, the area or the volume using laser beam (2). An influence of scattered radiation (9) on the image is reduced by spatial filtering. The image is corrected using geometric data of the component, the area, or the volume, in order to obtain a thickness profile of the component, the area, or the volume based on the image. An independent claim is also included for a method for determining moisture content of a component.