Thermographic Basis Weight Correlation for Coated Metal Sheet Scanning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing measurement systems for basis weight and thickness of sheet materials, particularly in lithium-ion battery production, face challenges in accurately measuring across the entire width and length due to limited scanning capabilities and non-uniform cooling effects, leading to incomplete data and reduced quality control.
Innovation Solution
Correlating thermographic image data with online scanning basis weight measurements to derive more comprehensive basis weight profiles by using a scanning beta gauge and infrared temperature sensors, which account for sheet cooling conditions and edge effects, allowing for continuous and accurate quality control across the entire cross direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a scanning sensor is used to measure basis weight across the sheet width, then measurement coverage is improved, but measurement precision deteriorates due to diagonal scanning paths and zig-zag patterns
Solution Approach 1:
The patent replaces the mechanical scanning sensor system with an optical-infrared thermographic system. Instead of using a physical scanner that moves mechanically across the sheet creating diagonal paths, the invention uses an infrared camera to capture thermal images that directly correspond to basis weight variations through thermal radiation detection, eliminating the zig-zag scanning error entirely
Solution Approach 2:
The patent utilizes thermal radiation detection where variations in basis weight cause corresponding variations in thermal emission. The infrared camera detects these thermal differences as intensity variations in the thermographic image, creating a visual 'color' map of basis weight distribution across the sheet without mechanical scanning
2Loss of information
If last averages are calculated after each scan to provide control data, then measurement completeness is improved, but loss of time increases due to delayed data availability
Solution Approach 1:
The patent captures complete thermographic images of the entire sheet width simultaneously as the sheet passes through, rather than scanning across it sequentially. This preliminary capture of all spatial information at once eliminates the time delay associated with completing a full scan before calculations can begin, providing immediate data for control actions
Solution Approach 2:
The patent transitions from sequential one-dimensional scanning measurement to simultaneous two-dimensional thermographic imaging. By capturing the entire cross-section of the sheet in a single instantaneous thermal image, the system gains both complete spatial coverage and immediate data availability, eliminating the time-completeness tradeoff
3Device complexity
If fixed-point sensors are used to measure sheet properties, then device complexity is reduced, but area of measurement deteriorates due to limited number of sensors
Solution Approach 1:
The patent replaces multiple discrete fixed-point sensors with a single infrared thermographic camera system. This optical system captures thermal radiation from the entire sheet width simultaneously through a two-dimensional detector array, achieving comprehensive area coverage with a single integrated device rather than numerous separate sensors
Solution Approach 2:
The infrared thermographic camera serves multiple functions simultaneously: it provides spatially resolved basis weight measurement across the entire sheet width, maintains simple device architecture, and enables real-time monitoring. This single universal device replaces what would otherwise require multiple specialized fixed-point sensors positioned across the sheet
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
This approach provides enhanced quality measurement data at an early production stage, enabling better process control and reducing scrap rates by ensuring uniformity and accuracy in basis weight and thickness measurements across the entire sheet.
Implementation Method 1
an infrared temperature sensor... measure the temperature of the traveling sheet material
Implementation Method 2
a thermographic image of the traveling sheet material is taken at a first position
Data Source
Figure 1A
Figure 1B
Figure 2~3
AI summary
Areal weight or thickness of a moving coated metal sheet along its entire cross directional width is derived by correlating thermographic image data to online, scanning basis weight measurements. Thermal imaging camera (22) captures thermal images of a heated moving coated metal sheet material (42) along a cross direction at a first position along the machine direction to generate sequential temperature profiles. Scanning beta gauge (74, 76) measures the areal weight of the moving coated metal sheet downstream at a second position. An infrared temperature sensor (78) also measures the temperature of the moving coated metal sheet which is at a lower temperature at or near the second position. The temperature differential between the cross directional thermographic image data and the latter infrared temperature is a function of the basis weight. Basis weight measurements from the beta gauge is used to extrapolate cross directional basis weight data.