Rolling Gap Compensation for Roll Eccentricity in Flat Rolling Mills
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rolling frame technologies face challenges in accurately correcting total eccentricity in all possible case constellations, regardless of which rollers are involved, during the rolling of flat metal products, leading to inefficiencies and inaccuracies in the rolling process.
Innovation Solution
An operating procedure for the rolling frame that minimizes a cost function by rotating the upper and lower roller sets during roll breaks, using first and second derivatives of overall eccentricity to adjust the rolling gap, allowing for precise compensation of eccentricities caused by both working and retaining rollers, even when some rollers' rotations are not recorded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only the rotations of driven rollers are recorded and undriven rollers' rotations are determined from driven rollers, then the device complexity is reduced, but the measurement precision of roller rotations deteriorates due to accumulation of deviation over several revolutions
Solution Approach 1:
The patent applies preliminary action by synchronizing undriven rollers with driven rollers at the beginning of each rolling operation. Rotation transmitters on undriven rollers are reset to a reference position before rolling starts, establishing an accurate initial state. This preliminary synchronization prevents accumulation of deviation errors that would occur if rotations were merely calculated from driven rollers without periodic re-synchronization.
2Manufacturing precision
If rolling gap is continuously adjusted to compensate for eccentricity, then the manufacturing precision of flat rolled material is improved, but the productivity decreases due to time-consuming adjustments
Solution Approach 1:
The patent implements periodic action by performing eccentricity compensation adjustments at specific intervals - at the beginning of each rolling operation and after a predetermined number of rolling operations. Instead of continuous adjustment during the entire rolling process, the system periodically corrects the rolling gap based on detected eccentricity, maintaining precision while minimizing interruption to production flow.
3Measurement precision
If rotation transmitters are installed on all rollers including undriven rollers, then the measurement precision of all roller rotations is improved, but the device complexity and cost increase
Solution Approach 1:
The patent applies segmentation by dividing rollers into two categories: driven rollers equipped with rotation transmitters for accurate rotation measurement, and undriven rollers without transmitters whose rotations are determined through synchronization with driven rollers. This segmentation reduces the total number of rotation transmitters needed while maintaining sufficient measurement precision through the synchronization mechanism that periodically aligns undriven rollers with their driven counterparts.
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A roll stand for rolling a flat rolling material (3) made of metal has an upper set (U) of rolls and a lower set (L) of rolls with corresponding working rolls (1U, 1L) and support rolls (2U, 2L). The flat rolling material (3) is rolled during a normal operation. In this way, based on first and second variables (RUB, RLB, φ1UB, φ1LB, RUW, RLW, φ2UW, φ2LW) that are characteristic for an eccentricity of the support rolls (2U, 2L) and the working rolls (1U, 1L) of the roll stand according to an angular position (φ UB, φ UW, φ LB, φ LW) of at least one roll (1U, 1L, 2U, 2L) of the roll stand, a control device (4) continuously determines a compensation value (ε) that is dependent on the angular position (φ UB, φ UW, φ LB, φ LW). The control device (4) corrects a roll gap target value (s*) for the roll stand with the compensation value (ε) and correspondingly acts on the roll frame. In this way, the angular positions (φ UB, φ UW, φ LB, φ LW) of only the working rolls (1U, 1L) or only the support rolls (2U, 2L) of the roll frame are detected. The angular positions (φ UB, φ UW, φ LB, φ LW) of the other rolls (1U, 1L, 2U, 2L) are determined from the detected angular positions (φ UB, φ UW, φ LB, φ LW). However, for the determined angular positions (φ UB, φ UW, φ LB, φ LW), the respective occurrence of a reference angular position is detected and supplied to the control device (4).