Rolling Mill Tension Control for Lead-Free Strip Start-Up
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Solution Overview
Problem
The existing rolling device configurations require a lead material to be bonded to the metal strip for starting the rolling process, which is burdensome and costly, and does not allow for efficient rolling of the metal strip from the tip side without additional equipment.
Innovation Solution
A control device is used to adjust the rolling mill rolls and apply tension to the metal strip, allowing the rolling process to start from the tip side without a lead material by increasing the entrance-side tension while maintaining zero exit-side tension, thereby improving yield with a simpler configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a lead material is bonded to the tip part of the metal strip to start rolling, then the rolling can be started from the tip side and yield is improved, but the device complexity increases due to need for bonding equipment and the process becomes burdensome
Solution Approach 1:
The invention extracts and eliminates the lead material bonding process from the rolling start procedure. By controlling the unwinding device to apply only entrance-side tension without exit-side tension, the metal strip can be fed into the rolling mill rolls directly from the tip side without requiring any lead material or bonding equipment, thus simplifying the device configuration while maintaining improved yield.
Solution Approach 2:
The invention changes the tension parameters during the rolling start process. Specifically, it controls the unwinding device to maintain entrance-side tension greater than zero while keeping exit-side tension equal to zero. This parameter change enables the metal strip to be fed smoothly into the rolling mill rolls from the tip side without lead material, resolving the contradiction between yield improvement and device complexity.
2Reliability
If the metal strip is wound around the winding device when starting to roll, then the rolling can be performed with tension control, but the portion of the metal strip closer to the winding device than the rolling mill rolls cannot be rolled and cannot be formed into a product
Solution Approach 1:
The invention inverts the conventional rolling start approach. Instead of winding the metal strip around the winding device first and then starting to roll, it feeds the tip part of the metal strip directly into the rolling mill rolls while controlling tension through the unwinding device. This inversion allows the entire metal strip including the tip portion to be rolled and formed into product, eliminating the yield loss while maintaining reliable tension control.
3Ease of operation
If the rolling mill rolls are pressed and rotated immediately without passing the tip part through, then the process is simpler, but the tip part of the metal strip cannot be fed properly and yield is reduced
Solution Approach 1:
The invention performs a preliminary action by passing the tip part of the metal strip through the rolling mill rolls before applying full pressing and rotation. The control device controls the unwinding device to feed the tip part into the rolling mill rolls while maintaining appropriate tension, ensuring proper feeding and alignment before the rolling process begins, thus preventing yield loss while keeping the process simple.
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 enables efficient rolling of the metal strip from the tip side without using a lead material, improving yield and reducing operational costs by using a simpler configuration that effectively suppresses meandering and slipping.
Implementation Method 1
a rolling device (reverse mill) for rolling a metal strip by moving the metal strip, which is passed through a pair of rolling mill rolls, back and forth
Implementation Method 2
applying tension to the metal strip by the unwinding device and the winding device
Data Source
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AI summary
A control device for controlling a rolling device which includes a pair of rolling mill rolls provided to sandwich a metal strip and an unwinding device uncoiling the metal strip at an entrance side of the rolling mill rolls in a traveling direction of the metal strip and which is configured to roll the metal strip by the pair of rolling mill rolls is configured to: after passing a tip part of the metal strip through the pair of rolling mill rolls in a state where a gap between the pair of rolling mill rolls is larger than a strip thickness of the metal strip, press the metal strip by the pair of rolling mill rolls in a state where exit-side tension applied to the metal strip is zero; make entrance-side tension applied to the metal strip by the unwinding device become larger than zero; and start rotation of the pair of rolling mill rolls.