Strip Thickness Target Adjustment Using Predicted Rolling Profiles
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Solution Overview
Problem
Existing methods for controlling strip thickness during hot and cold rolling often result in a high proportion of rolled strip not meeting quality criteria and low productivity, particularly in the edge areas, leading to scrap and suboptimal mill operation.
Innovation Solution
A method for adjusting the target thickness value by generating a predicted thickness profile based on maximum, minimum, and mean values, and adjusting the mean value to ensure the strip meets customer tolerances, optimizing the fillet area quality and increasing yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the strip thickness is controlled to the middle of the strip width, then the thickness control is simple, but a relatively high proportion of the rolled strip does not meet the required quality criteria and productivity is low
Solution Approach 1:
The patent divides the strip width into multiple measurement positions (edge area and middle area) and determines target thickness values for each position separately. This segmentation allows the control system to account for thickness variations across the width, improving overall product quality without significantly increasing system complexity
Solution Approach 2:
The patent applies different target thickness values to different regions of the strip (edge area versus middle area). By determining position-specific target values based on local thickness characteristics, the system optimizes quality in each region while maintaining a relatively simple control approach
2Manufacturing precision
If the strip thickness is controlled to meet end customer specifications, then the product quality meets customer demands, but significantly better qualities are not utilized and the mill is not operated to deliver maximum yield
Solution Approach 1:
The patent determines target thickness values for the next strip to be rolled based on historical data and predicted thickness profiles before the rolling process begins. This preliminary determination allows optimization of both quality and yield by pre-calculating target values that account for expected variations, enabling the mill to operate at maximum yield while ensuring customer specifications are met
Solution Approach 2:
The patent uses historical thickness measurement data from previously rolled strips to inform target thickness value determination for future strips. This feedback mechanism allows the system to learn from past performance and continuously optimize both quality and productivity, utilizing better than customer-demanded qualities to maximize mill yield
3Manufacturing precision
If the target thickness value is set according to end customer specifications, then the strip meets customer tolerances, but the fillet area quality is not optimized and scrap is generated
Solution Approach 1:
The patent determines separate target thickness values for the edge area and middle area of the strip, recognizing that different regions have different quality requirements. By optimizing the target value for the fillet area (edge region) separately from the middle area, the system ensures customer tolerance compliance while maximizing fillet area quality and minimizing scrap generation
Solution Approach 2:
The patent predicts the thickness profile of the next strip to be rolled and determines adjusted target thickness values before the rolling process begins. This preliminary action allows the system to pre-compensate for expected variations, ensuring that the fillet area meets both customer tolerances and quality optimization criteria, thereby reducing scrap
Data Source
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AI summary
The invention relates to a method and a computer program for adjusting the target thickness value for controlling the thickness of a strip to be newly rolled, in particular a metal strip, using at least one rolling stand. According to the method, the thickness profile of at least one previously rolled strip is first analyzed at a first width position with regard to the maximum and/or minimum value over at least one length section, and an average value is determined. To achieve a higher yield of 1A-quality strip after hot or cold rolling than in the prior art, a predicted thickness profile DP for the newly rolled strip is determined according to the invention, based on the analyzed and determined values.The system then checks whether the distance dAct between the predicted maximum value hpmx and the predicted minimum value hpmi for the predicted thickness profile DP is smaller than the distance dRef between a target upper limit Vo and a target lower limit Vu of a given tolerance band. If so, the mean value hp of the predicted thickness profile is either increased towards the target upper limit VO or decreased towards the target lower limit Vu, and the resulting mean value hpn is then set as the adjusted target thickness value for the new strip to be rolled over the length section l'.