Stretch-Bending Straightening Control for Strip Flatness
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Solution Overview
Problem
Existing stretch-bending directional systems for metallic tapes struggle to optimize the quality of the material by effectively minimizing internal tensions and wavy deformations, which are caused by varying fiber lengths, leading to suboptimal planism and quality issues.
Innovation Solution
A stretch-bending directional system with dual measuring systems in the pick-up and pull-down areas, utilizing a single controller to determine deviations from setpoint values and adjust the bending process, allowing for selection between two closed control loops based on empirical values or material characteristics to optimize the directional process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single measuring system is used in the pull-down area, then the device complexity is reduced, but the manufacturing precision and quality optimization capability deteriorate due to increased dead distance and inability to capture early deformations
Solution Approach 1:
The measuring system is segmented into two independent measuring systems: one in the pull-up area and one in the pull-down area. Each measuring system independently monitors strip deformations in its respective zone, allowing the control system to select the most appropriate measurement data for optimization. This segmentation eliminates the dead distance problem by providing measurement capability at multiple locations along the material path.
Solution Approach 2:
The invention adds a spatial dimension to measurement by placing measuring systems at two different locations (pull-up and pull-down areas) rather than relying on a single measurement point. This dimensional expansion allows the system to capture deformation information earlier in the process and provides redundant measurement data for more robust control decisions.
2Manufacturing precision
If the measuring roller is placed close to the bending-straightening unit, then the dead distance is minimized, but the measuring system becomes more sensitive to high strip tensions that may mask deformation signals
Solution Approach 1:
The measurement function is segmented across two zones: the pull-up area measuring system operates in the high-tension region close to the bending-straightening unit with minimal dead distance, while the pull-down area measuring system operates in the lower-tension region where deformation signals are more detectable. This segmentation allows each system to be optimized for its specific operational conditions.
Solution Approach 2:
The system changes the operational parameters (tension level, measurement location) by providing two different measuring systems that operate under different conditions. The controller selects which measuring system to use based on the specific strip characteristics and process requirements, effectively changing the measurement parameters to match the optimal detection conditions.
3Adaptability or versatility
If dual measuring systems with selection capability are implemented, then the adaptability and quality optimization are improved, but the device complexity and control system complexity increase
Solution Approach 1:
The control system is designed to dynamically select between the two measuring systems based on real-time process conditions, strip characteristics, and quality requirements. This dynamic selection capability allows the system to adapt to varying conditions without requiring manual reconfiguration, optimizing the straightening process for different material types and deformation patterns.
Solution Approach 2:
The controller is designed with multi-functionality to handle both measuring systems and make intelligent selection between them. This universal control approach consolidates the complexity into a single control unit that can manage multiple measurement sources and determine the optimal control variables, rather than requiring separate control systems for each measuring system.
4Manufacturing precision
If support rollers are made adjustable to compensate for edge waves, then the manufacturing precision is improved, but the device complexity and adjustment complexity increase
Solution Approach 1:
The adjustable support rollers are integrated with the measuring systems to form closed-loop control systems. The measuring systems continuously monitor strip flatness and provide feedback to the controller, which automatically adjusts the support roller positions to compensate for detected deformations such as edge waves. This automated feedback mechanism eliminates the need for manual setup and adjustment, simplifying operation while maintaining high precision.
Solution Approach 2:
The system performs self-adjustment through the automated control loops that use measurement data to automatically modify support roller positions. The process compensates for its own deviations without requiring external intervention or complex manual setup procedures, making the system easier to operate while maintaining manufacturing precision.
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 enables the production of high-quality band-shaped materials by accurately adapting to unplannies, reducing residual stresses and improving material flatness, with the ability to switch between control loops dynamically based on real-time measurements and material properties.
Implementation Method 1
Different forces from the strip or strip-shaped material 10, caused by the unevenness, are transmitted directly to the sensors via adjacent segments.
Implementation Method 2
the strip-shaped material 10, fed in the direction of travel 24 from a coil arranged on a reel, is subjected to a stretching zone by means of a braking S-block 16 and a tensioning S-block 18. In this zone, the strip-shaped material 10 is stretched.
Implementation Method 3
the strip is subjected to alternating bends in the bend-straightening unit 26. These two measures align the shorter fibers with the longer ones and reduce residual stresses.
Data Source
Figure 1~3
Figure 2
Figure 4a~5d
AI summary
In a stretching-bending-straightening system and a method for the actuation thereof, material in strip form is fed to a high-tension region (50) and a low-tension region (52), wherein the low-tension region (52) is arranged downstream of the high-tension region (50). A bending-straightening unit is arranged in the high-tension region (50). A measuring system determines first measured values in the high-tension region (50). A controller (C) is intended and suitable for determining a deviation of the first measured values from a setpoint value of the bending-straightening result and for determining at least one manipulated variable for the bending-straightening unit in dependence on the determined deviation within a first closed control loop. By additionally providing at least one measuring system for determining second measured values in the low-tension region, by having a controller (C) intended and suitable for determining a deviation of the second measured values from the setpoint value of the bending-straightening result and for determining the at least one manipulated variable in dependence on the determined deviation within a second closed control loop, and by providing selecting means that are intended and suitable for selecting the first or second closed control loop for reducing the deviation of the first and/or second measured values from the predetermined or predeterminable setpoint value, a stretching-bending-straightening system and a method for the actuation thereof are designed in such a way that the quality of the strips processed thereby is increased.