Rolling Mill Roll Gap Control Using Direct Backup Roll Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for determining the roll gap between work rolls during metallic strip rolling are inaccurate due to reliance on imprecise mathematical models, frictional force distortions, and wear on rolls, leading to errors in calculating the actual thickness of the roll gap.
Innovation Solution
A device and method that utilize direct measurement of support roll movement by sensors to calculate the roll stand elongation, eliminating the need for inexact mathematical models and accounting for eccentricity, with a control device adjusting the roll gap to a desired target value by controlling hydraulic cylinders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If mathematical models are used to convert stand characteristic curves to actual strip width, then the determination can be performed for narrower strips, but the accuracy deteriorates due to model inexactness
Solution Approach 1:
The patent replaces mathematical modeling with direct optical measurement. Instead of using imprecise mathematical models to calculate roll gap from stand characteristic curves, the invention uses optical sensors (laser triangulation sensors or confocal sensors) to directly measure the distance between work rolls, eliminating model-dependent errors and providing accurate measurements for strip widths of any proportion relative to roll width
Solution Approach 2:
The patent introduces optical sensors as intermediary measurement devices between the rolling stand and the control system. These sensors serve as mediators that directly detect the roll gap distance without requiring mathematical conversion, thereby improving measurement accuracy while maintaining versatility for different strip widths
2Measurement precision
If force measurement is used to calculate stand elongation, then the roll gap can be determined, but the measurement precision deteriorates due to friction forces distorting the force measurement
Solution Approach 1:
The patent replaces force-based mechanical measurement with optical distance measurement. Instead of measuring rolling forces and calculating elongation (which is distorted by friction), the invention directly measures the distance between work rolls using optical sensors, completely eliminating friction-related measurement errors
Solution Approach 2:
The patent extracts the measurement function from the force measurement system and creates a separate optical measurement system. By taking out the distance measurement function and implementing it independently through optical sensors, the system eliminates the harmful influence of friction forces on measurement accuracy
3Ease of manufacture
If the stand characteristic curve is determined without rolled material, then the curve can be measured directly, but the actual roll gap during rolling cannot be accurately determined due to stand elastic elongation
Solution Approach 1:
The patent replaces indirect calculation based on stand characteristic curves with direct optical measurement. Instead of determining curves without material and calculating elongation, the invention directly measures the actual distance between work rolls during rolling using optical sensors, providing accurate real-time data regardless of stand elastic deformation
Solution Approach 2:
The patent performs preliminary calibration by establishing the relationship between sensor signals and actual distances, then uses this calibration to directly determine roll gap during rolling. This preliminary setup enables accurate direct measurement without requiring separate characteristic curve determination and elongation calculation steps
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 significantly improves the accuracy of roll gap determination and adjustment, reducing errors and allowing for precise control of the roll gap thickness during metallic strip rolling.
Implementation Method 1
with which a distance of a support roll (18, 20) at at least one point therefrom to a predetermined reference point (P1, P2) is measured by a sensor (24, 25)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a device (10) and a method for rolling a metal strip. According to the invention, a distance between the upper/lower backup roll (18; 20) at at least one point thereof in each case and a predefined upper/lower reference point (P1; P2) is measured by an upper/lower sensor (25) and the measured values from the sensors are transmitted to a control device. Strain on the roll stand (12) is calculated using a mathematical model taking into account the roll force produced. By means of the control device, an absolute size of the roll gap and thus the resulting thickness of the rolling stock is determined on the basis of the measured positions of the backup rolls (18; 20) and the calculated strain on the roll stand (12), and, by means of the control device, this absolute value for the roll gap is compared with a target value for the roll gap and, on the basis thereof, at least one backup roll (18; 20) is then vertically adjusted in order to set the roll gap to the target value in a controlled manner.