Rod Article Quality Inspection with Dual-Accuracy Measurement
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Solution Overview
Problem
In the tobacco industry, existing quality inspection systems for rod-like articles face challenges in accurately measuring quality parameters at high speeds, leading to measurement errors and incorrect classification of good or defective articles, especially when parameters are close to acceptable limits, resulting in potential rejection of non-defective products.
Innovation Solution
A method and system that involves an initial measurement of quality parameters with a first measuring unit, dividing articles into streams based on acceptable values, with articles near limit values undergoing repeated inspection using a second measuring unit of higher accuracy to verify measurements, ensuring only defective articles are rejected and reducing production waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If measurements are conducted at high manufacturing speeds, then productivity is improved, but measurement precision deteriorates due to increased dynamics and measurement interferences
Solution Approach 1:
The system performs a preliminary measurement with the first measuring unit at high manufacturing speed, then directs articles near the decision boundary to a second measuring unit for more accurate measurement. This preliminary action allows the system to maintain high productivity while ensuring accurate measurements for critical cases.
Solution Approach 2:
The system applies different measurement qualities to different articles based on their measured parameter values. Articles with values close to the decision boundary receive higher measurement quality (second measuring unit with higher accuracy), while articles with clearly acceptable or rejectable values receive standard measurement quality (first measuring unit).
2Measurement precision
If a single measuring unit with high accuracy is used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The measuring system is segmented into two separate measuring units with different accuracy levels. The first measuring unit handles the majority of measurements at standard accuracy, while the second measuring unit handles only the subset of articles near the decision boundary with high accuracy. This segmentation reduces overall system complexity compared to using a single high-accuracy unit for all measurements.
Solution Approach 2:
The system applies high-accuracy measurement only partially, specifically to articles that require it (those near the decision boundary), rather than applying high-accuracy measurement to all articles. This partial action reduces the burden on the measuring system while maintaining sufficient accuracy for decision-making.
3Reliability
If all articles with parameters near limit values are rejected, then reliability is improved by eliminating defective articles, but loss of substance increases due to rejection of potentially good articles
Solution Approach 1:
The system uses feedback from the first measurement to determine whether an article should undergo second measurement or be directly accepted/rejected. Articles near the decision boundary receive feedback to undergo additional measurement, while articles with clear quality status receive feedback for direct disposition. This feedback mechanism improves reliability by verifying borderline cases while minimizing waste of clearly good articles.
Solution Approach 2:
The system changes the measurement parameter accuracy for different articles based on their initial measurement results. Articles with values close to the decision boundary are measured with higher accuracy (second measuring unit), while other articles are measured with standard accuracy (first measuring unit). This parameter change allows reliable quality control while reducing unnecessary rejections of good articles.
4Measurement precision
If repeated measurement with higher accuracy is performed for all articles, then measurement precision is improved, but loss of time increases due to additional inspection steps
Solution Approach 1:
The system performs the time-consuming second measurement only partially, specifically for articles near the decision boundary that require higher accuracy for proper classification. The majority of articles are processed through the first measuring unit only, minimizing the time loss associated with repeated measurement while maintaining precision where needed.
Data Source
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AI summary
The system for manufacturing rod-like articles, comprising a first measuring unit (5) for measuring at least one quality parameter of the manufactured rod-like articles (7), which measures with a first measuring accuracy, whereas the said quality parameter has a predefined range of acceptable values of the parameter, a device for dividing a stream of the rod-like articles into a first stream including the rod-like articles having said at least one quality parameter which falls within the range of the acceptable values of the parameter and into a second stream of the rod-like articles, having the said at least one quality parameter which does not fall within the range of the acceptable values of the parameter, a first transferring device (22), which receives the first stream of the rod-like articles and transfers this stream as an output stream of the rod-like articles manufacturing system, wherein it is moreover equipped with a device for a repeated inspection of the said quality parameter, including a measuring conveyor (17) which receives the second stream of the rod-like articles and a second measuring unit (24) which effects a repeated measurement of the said quality parameter of the rod-like article with a second measuring accuracy higher than the first measuring accuracy of the first measuring unit, whereas the device for the repeated inspection of the said quality parameter belongs to the repeated quality inspection path, a second transferring device (25) which transfers the inspected rod-like article to the output stream of the rod-like articles on the first transferring device, when the result of the repeated inspection of the said at least one quality parameter for an individual rod-like article falls within the range of the acceptable values of the said parameter.