Optical Thickness Measurement for Plastic Containers
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Solution Overview
Problem
Conventional high-speed measurement systems for determining the wall thickness of plastic containers, such as PET bottles, lose accuracy at manufacturing speeds and can only capture a limited number of data points, failing to provide comprehensive thickness measurements.
Innovation Solution
A high-speed optical measurement system utilizing light sources and detectors, coordinated by a computer system, which emits light of specific wavelengths absorbed by the material, allowing for accurate thickness determination through correlation with absorbance spectra, and providing real-time feedback for material control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional high-speed measurement systems are used to measure container wall thickness at manufacturing speeds, then measurement speed is improved, but measurement precision deteriorates to about 20 μm
Solution Approach 1:
The patent replaces conventional mechanical or contact-based thickness measurement systems with an optical measurement system that uses light transmission through the container walls. This optical substitution enables high-speed non-contact measurement while achieving superior precision of 1 μm or better, resolving the contradiction between speed and accuracy by fundamentally changing the measurement physics from mechanical to optical domain
Solution Approach 2:
The invention changes the measurement parameters by using multiple wavelengths of light and analyzing transmission characteristics across different spectral bands. By measuring at multiple wavelengths and applying advanced signal processing, the system achieves both high speed operation and enhanced precision through parameter multiplication rather than simple single-point measurement
2Productivity
If conventional high-speed measurement systems are used, then measurement speed is improved, but the number of data points captured per container is reduced
Solution Approach 1:
The patent segments the measurement process into multiple wavelength channels, with each wavelength providing independent transmission data. This segmentation across spectral bands allows the system to capture comprehensive data points throughout the container structure at high speed, as each wavelength segment contributes additional information about different wall regions and thickness variations
Solution Approach 2:
The invention adds the spectral dimension to the measurement by utilizing multiple wavelengths of light. This transforms a single-dimensional spatial measurement into a multi-dimensional measurement that combines spatial information with spectral information, enabling comprehensive data capture across both the container surface and wavelength domains simultaneously at high speed
3Measurement precision
If conventional measurement systems are used to achieve 1 μm accuracy, then measurement precision is improved, but measurement speed deteriorates and cannot handle manufacturing speeds
Solution Approach 1:
The patent replaces slow conventional measurement methods with high-speed optical detection systems that can capture transmission data at manufacturing line speeds. The optical system combined with rapid photodetectors and fast processing electronics enables both 1 μm precision and high productivity by operating in the optical domain where measurement can occur without mechanical contact or slow scanning
4Loss of information
If conventional systems are used to capture more data points, then measurement comprehensiveness is improved, but measurement speed deteriorates
Solution Approach 1:
The patent implements continuous optical measurement across the entire container surface as it moves through the production line. Rather than discrete spot measurements that require sequential scanning, the system maintains continuous illumination and detection across multiple wavelengths simultaneously, capturing comprehensive data at every position along the container without interrupting production flow
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 accurate and comprehensive wall thickness measurements of plastic containers during manufacturing, improving material efficiency and production control by correlating light absorption with thickness, thus enhancing the precision and speed of the measurement process.
Implementation Method 1
The light source can be configured to emit light in a band of wavelengths known to be absorbed by the material
Implementation Method 2
determine the thickness of the material or the article of manufacture from light transmitted through the material or the article of manufacture in accordance with a known relationship of absorbance to thickness for the material or the article of manufacture
Data Source
AI summary
Systems and methods are provided for determining a thickness of a material or an article of manufacture thereof such as a wall thickness of a plastic container or plastic bottle during manufacturing. In some embodiments, for example, a measurement system can include a light source disposed adjacent to a production line for plastic bottles. The light source can be configured to transmit light of a known frequency through the plastic bottles. A camera can be disposed opposite the light source. The camera can be configured to receive the light transmitted through the plastic bottles. An optional trigger, when present, can be configured to coordinate timing of the camera and the light source. A computer can be configured to determine wall thicknesses for the plastic bottles by an experimentally determined correlation between the light received by the camera and a known absorbance spectrum of the material forming the plastic bottles.