Rolling Mill Stand Speed Control for Faster Strip Threading
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Solution Overview
Problem
Existing rolling mill operations aim to increase productivity without altering the mechanical configuration, particularly through optimizing process control to enhance threading speed and reduce idle times.
Innovation Solution
An operating method for a rolling mill that involves controlling the speed of individual rolling stands using higher-level process control, allowing for variable mass flow by calculating maximum possible threading speeds while adhering to technical limits and process parameters, ensuring the metal strip's speed is optimized throughout the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If constant speed is used for rolling stands during threading, then temperature control is maintained, but threading speed is limited and productivity is reduced
Solution Approach 1:
The patent applies dynamics by transitioning from constant speed control to variable speed control of rolling stands. The speed of each rolling stand is dynamically adjusted based on the position of the strip head and the thickness reduction ratio, allowing the system to adapt speed in real-time during the threading process. This enables faster threading while maintaining proper temperature control through coordinated speed variations.
Solution Approach 2:
The patent changes the speed parameter of rolling stands from a constant value to a variable value that depends on the threading phase. By calculating optimal speeds based on thickness reduction ratios and strip position, the system optimizes threading speed without compromising temperature control, directly addressing the productivity-time loss contradiction.
2Productivity
If maximum threading speed is used, then productivity increases, but temperature control becomes difficult
Solution Approach 1:
The patent dynamically adjusts the speed parameter of rolling stands based on the threading phase and thickness reduction requirements. By calculating optimal speeds that balance threading efficiency with temperature control needs, the system achieves high productivity while maintaining proper temperature profiles through coordinated parameter changes across multiple rolling stands.
Solution Approach 2:
The patent applies different speed control strategies to different rolling stands based on their specific function and position in the threading sequence. Each rolling stand operates at an optimized speed tailored to its local requirements, allowing maximum threading speed in some areas while maintaining temperature control in others, thus resolving the contradiction between productivity and temperature control.
3Productivity
If constant speed operation is maintained, then process stability is ensured, but idle times between strips increase
Solution Approach 1:
The patent implements dynamic speed control that adapts to the threading phase and strip characteristics. By accelerating rolling stands during critical threading phases and coordinating speed changes across stands, the system reduces idle times between strips while maintaining process stability through controlled transitions, directly improving production rate without sacrificing stability.
4Productivity
If mechanical configuration is changed to increase productivity, then throughput improves, but device complexity and cost increase
Solution Approach 1:
The patent replaces mechanical modifications with a control-based solution. Instead of changing the physical configuration of rolling stands or adding mechanical acceleration devices, the system uses sophisticated speed control algorithms and coordination strategies to achieve higher productivity. This substitution of mechanical changes with control system optimization increases throughput while avoiding increased device complexity.
Data Source
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AI summary
The invention relates to an operating method for a rolling mill comprising several rolling stands (F1-Fn) through which a metal strip passes, wherein the metal strip is successively threaded into at least some of the rolling stands (F1-Fn) and the metal strip passes through the rolling mill with stepwise thickness reduction from an initial thickness to a target thickness, wherein the method comprises speed control of the individual rolling stands (F1-Fn) by means of a higher-level process control, and wherein at least the entry speed of the metal strip into the rolling mill and/or the speed of the rolling stands (F1-Fn) when threading a strip head and/or a strip foot or a planned section change of the metal strip into the rolling stands (F1-Fn) is controlled according to a speed specification for the metal strip or for parts of the metal strip.