Cold Rolling Mill Thickness Control via Indirect Roll-Out Speed Reconstruction
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Solution Overview
Problem
Existing methods for controlling the thickness of rolled strips in mill trains face inaccuracies due to vibrations and measuring errors at the roll-out speed measurement, leading to reduced reliability and increased costs.
Innovation Solution
The method reconstructs the roll-out speed of the rolled strip by measuring the roll-in speed and thickness before the roll gap, using the tangential speed of the operating rolls, and correcting the thickness after the roll gap with a transit time element, eliminating the need for direct roll-out speed measurement and enhancing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the roll-out speed is measured directly after the roll gap, then the thickness control can be performed, but vibrations and measuring errors reduce the reliability and accuracy
Solution Approach 1:
The patent introduces an intermediary calculation method that uses the tangential speed of the rolls as a mediator to derive the roll-out speed indirectly, rather than measuring it directly. This intermediary approach filters out vibrations and measuring errors that would affect direct measurement, thereby improving both reliability and accuracy of the thickness control
Solution Approach 2:
The patent replaces the mechanical measurement system (direct speed measurement devices) with a calculation-based system that uses known parameters (roll tangential speed, mass flow conservation) to determine roll-out speed. This substitution eliminates the problematic direct measurement while maintaining the necessary control functionality
2Measurement precision
If a measuring instrument is used to measure roll-out speed, then thickness control is enabled, but costs increase and reliability decreases
Solution Approach 1:
The patent extracts the roll-out speed measurement function from the physical measurement instrument and relocates it to a calculation process. By taking out the measurement requirement and replacing it with computational derivation using existing data (roll tangential speed and mass flow), the system eliminates the need for additional measuring instruments, reducing complexity and cost while maintaining thickness control capability
Solution Approach 2:
The system uses its own existing parameters (roll tangential speed, measured thickness, mass flow relationships) to self-determine the roll-out speed without external measurement instruments. The mill train operation data itself provides the necessary information for calculation, making the system self-sufficient and eliminating dependency on additional measuring devices
Data Source
AI summary
One embodiment of the present invention discloses a method for operating a mill train, in particular used in a cold-rolling mill. The mill train includes operating rolls with a roll gap disposed in-between through which a rolled strip is guided. With the method of at least one embodiment, the thickness and the roll-in speed of the rolled strip are measured in front of the roll gap. The roll-out speed of the rolled strip after the roll gap is reconstructed with the aid of the tangential speed of the operating rolls. The thickness after the roll gap is then determined with the aid of the thickness and the roll-in speed in front of the roll gap and the reconstructed roll-out speed.