Web Process Roll Defect Detection via Synchronization Marks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional web inspection systems struggle to accurately identify the source of repeating anomalies or defects in moving webs, particularly when rolls have similar diameters and undergo spatial distortion, making it difficult to determine the specific roll causing the issue.
Innovation Solution
An automated inspection system that correlates anomaly positions with roll synchronization signals, using synchronization marks and position data to identify the source of repeating anomalies, allowing for precise differentiation between rolls with similar diameters and accounting for spatial distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional web inspection systems are used to identify repeating defects, then defect detection capability is provided, but the ability to accurately identify the specific offending roll deteriorates when rolls have similar diameters
Solution Approach 1:
The patent introduces synchronization marks as intermediary elements attached to each roll. These marks serve as unique identifiers that mediate between the rolls and the inspection system, enabling precise identification of which specific roll caused a defect without requiring complex differentiation of rolls with similar diameters. The synchronization marks are detected by sensors to generate roll synchronization signals that correlate defects with specific rolls.
Solution Approach 2:
The system changes the identification parameter from physical roll characteristics (diameter, position) to temporal-spatial parameters (synchronization signal timing, web position at defect detection). By measuring the web position when a synchronization mark passes and comparing it with defect positions, the system can accurately identify the offending roll even when rolls have nominally the same diameter, accounting for slight variations and spatial distortion.
2Adaptability or versatility
If conventional inspection systems rely on a priori knowledge of roll diameters, then defect analysis can be performed, but the system becomes unable to detect undocumented roll changes
Solution Approach 1:
The system performs self-calibration by automatically measuring the actual circumference of each roll through the synchronization mark detection process. Instead of relying on pre-programmed roll diameter data, the system observes the web position at multiple consecutive synchronization events for each roll and calculates the actual circumference from these measurements. This self-service capability allows the system to adapt to undocumented roll changes while maintaining reliable defect source identification.
Solution Approach 2:
The system performs preliminary measurement of roll circumferences during normal operation before defect analysis is required. By continuously monitoring synchronization mark positions and calculating actual roll circumferences in advance, the system ensures that accurate roll identification data is available even when rolls are changed without documentation. This preliminary action eliminates the need for manual roll inventory updates.
3Measurement precision
If conventional systems do not account for spatial distortion of the web, then simpler processing is achieved, but accurate correlation between defect position and roll position becomes impossible
Solution Approach 1:
The system uses web position feedback from the synchronization mark detection to continuously monitor and compensate for spatial distortion. By measuring the actual web position at each synchronization event and comparing it with expected positions based on roll circumference, the system detects distortion and adjusts its calculations accordingly. This feedback mechanism enables accurate defect-to-roll correlation even when the web undergoes stretching or compression between the defect-causing roll and the inspection system.
4Measurement precision
If roll synchronization signals are used to identify defect sources, then accurate roll identification is achieved, but the system complexity increases
Solution Approach 1:
The patent extracts the identification function from the physical roll characteristics and places it in separate, easily detectable synchronization marks. Instead of trying to identify rolls through their physical properties (diameter, position, speed), the system extracts a simple temporal signal (when the synchronization mark passes) that can be detected by sensors. This separation simplifies the detection mechanism while maintaining accurate roll identification capability.
Data Source
AI summary
A manufacturing system includes rollers having synchronization marks to indicate complete rotations. Synchronization mark readers read the synchronization marks of the plurality of rollers and output roll synchronization signals. An encoder outputs a position signal indicative of a down-web distance of the web. An inspection system inspects the web and outputs anomaly data identifying positions of anomalies on the web. A synchronization unit receives the position signal from the encoder and the plurality of roll synchronization signals from the synchronization mark readers and converts the occurrence of each of the roll synchronization signals into down-web positions within a coordinate system associated with web process line. An analysis computer processes the anomaly data and the synchronization signals to identify repeated anomalies and to determine which of the rollers caused the repeated anomalies.