Tandem Cold Mill Thickness Control via Indirect Performance Measurement
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Solution Overview
Problem
Current thickness feed-forward control methods in tandem cold mills rely on direct measurement of hot rolled material performance, which is costly and lacks precision, failing to effectively account for performance fluctuations that lead to thickness deviations in cold rolled strips.
Innovation Solution
A performance feed-forward thickness control method that uses deformation resistance force measurements indirectly, calculated through load cells and empirical coefficients, to adjust rolling forces and ensure precise thickness control across frames in the tandem cold mill.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct measurement instruments are added to measure supplied material performance before the tandem cold mill, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent introduces an intermediary measurement approach by measuring rolling force at the first frame instead of directly measuring supplied material performance. The rolling force serves as a mediator that reflects the deformation resistance characteristics of the supplied material, enabling indirect measurement without adding complex direct measurement instruments before the tandem cold mill.
Solution Approach 2:
The patent creates a copy of the supplied material performance information by measuring rolling force characteristics at the first frame. Instead of measuring the actual supplied material properties directly, the system copies the performance information through the rolling force signal, which contains equivalent information about the supplied material's deformation resistance.
2Manufacturing precision
If traditional thickness feed-forward control is used based on supplied material thickness deviation, then instantaneous deviation is eliminated, but performance fluctuation effects are not accounted for
Solution Approach 1:
The patent implements feedback by using the measured rolling force at the first frame to adjust the feed-forward control parameters for subsequent frames. The rolling force measurement provides feedback information about the supplied material's actual performance, which is then used to compensate for performance fluctuations in the thickness control of downstream frames.
Solution Approach 2:
The patent changes the control parameter from simple thickness deviation to a composite parameter that includes both thickness deviation and rolling force (deformation resistance). This parameter change allows the control system to account for performance fluctuations by incorporating rolling force variations into the feed-forward control calculation for subsequent frames.
3Measurement precision
If multiple measuring instruments are added to measure supplied material performance, then measurement precision is improved, but equipment cost and maintenance requirements increase
Solution Approach 1:
The patent uses rolling force measurement as an intermediary that eliminates the need for multiple direct measurement instruments. By measuring rolling force at the first frame, the system obtains supplied material performance information without requiring additional expensive measurement equipment before the tandem cold mill, thereby reducing manufacturing cost and maintenance requirements.
Solution Approach 2:
The patent makes the rolling force measurement system multi-functional by using it for both thickness control and supplied material performance assessment. The same rolling force measurement serves dual purposes: controlling the thickness of the rolled strip and evaluating the performance characteristics of the supplied material, thereby eliminating the need for separate measurement instruments.
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 stabilizes the thickness of cold rolled strips by comprehensively considering deformation resistance and thickness, reducing fluctuations and ensuring precise thickness control, thereby enhancing the precision of finished products.
Implementation Method 1
providing a load cell on the frame Si, measuring the rolling force deviation ΔPi caused by the deformation resistance fluctuation of the frame Si
Data Source
AI summary
The present invention relates to the field of strip cold rolling, and in particular to a thickness control method for strips in a tandem cold mill. Frame S1 and one or more additional frames are selected as virtual indirect measuring instruments for the strip performance. A load cell is provided on the frames that are selected as the indirect measuring instruments for the strip performance, and deformation resistance fluctuation of the supplied materials of the frame S is calculated. Finally, the feed-forward adjustment amount of each frame is calculated. The present invention measures the deformation resistance of each section of the strip of the supplied materials through the selected frame, reducing the fluctuation of the thickness of the finished products of the strip and ensuring stable rolling.