Web End Detection Using Angular Velocity and Speed Averaging
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Solution Overview
Problem
Current methods for determining the end of a material web in web processing machines are unreliable, leading to imprecise timing for web changes and control signal triggering.
Innovation Solution
Measuring the angular velocity of the roll using rotary encoders and recording web speed to calculate web length, with averaging over time periods to account for disturbances, and using this information to trigger control signals for precise web end detection and processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional timing methods are used to determine web end, then the control system is simple, but the determination of web end time is imprecise and unreliable
Solution Approach 1:
The patent replaces conventional mechanical timing methods with an optical measurement system using a light barrier (Lichtschranke) to detect web position. This substitution of measurement principle enables precise determination of web end time while maintaining automated control, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent implements a feedback mechanism where the light barrier continuously monitors web position and provides real-time signals to the control system. This feedback enables dynamic adjustment and precise determination of web end time, improving measurement precision while the automated feedback loop manages the complexity of the control system.
2Adaptability or versatility
If web speed varies during processing, then flexibility in processing is improved, but timing accuracy for web end detection deteriorates
Solution Approach 1:
The patent uses periodic measurement cycles with the light barrier, where the web position is continuously monitored at regular intervals. This periodic action allows the system to adapt to varying web speeds while maintaining accurate timing determination through frequent position checks, resolving the contradiction between speed adaptability and timing accuracy.
3Quantity of substance
If the web thickness is large as in FFS machines, then material handling capability is improved, but measurement accuracy deteriorates due to increased slippage
Solution Approach 1:
The patent replaces mechanical speed measurement methods that are prone to slippage with an optical measurement system using a light barrier. This substitution eliminates the slippage issue entirely, as the optical method directly measures web position without mechanical contact, enabling accurate measurement even with thick webs in FFS machines.
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 method provides a more reliable and accurate prediction of the web end, minimizing web residue and ensuring precise timing for web changes and control signal triggering, especially in machines with large web wrap and low slippage, such as FFS machines and printing machines.
Implementation Method 1
The angular velocity of the roller can be measured by suitable rotary encoders monitoring the rotational movement of the roller
Implementation Method 2
which in each case acts in the form of a light barrier
Data Source
AI summary
The method for the controlling and/or monitoring of a web processing machine (1), in which at least one web (5) is unwound from the roller (12) of an unwinding device (11) and fed to the machine, and in which control signals are sent out in dependence upon the time point at which the web end is reached on the roller, entails recording the angular speed of the roller, recording the speed of the web, and determining the time point with consideration of these two values. An independent claim is included for a web processing machine controlled and/or monitored by the method according to the invention.