The requirements for the plate shape accuracy of aluminum foil products are getting higher and higher. At the same time, with the market demand for products and the improvement of equipment design and manufacturing level, the aluminum foil rolling mill is also developing to a wider range, which makes the shape of aluminum foil more and more in the rolling process. The harder it is to control. Due to the negative roll gap rolling, the roll tilt and hydraulic bending have no obvious control effect on the shape of the roll. At the same time, due to the relationship between the work roll and the support roll diameter ratio and the wider roll surface, the bending control is for the middle of the roll. The mechanical convexity control is basically invalid. At this time, although the roll cooling control of the roll thermal crown can reduce the local deviation of the plate shape remaining in the first two controls, the response speed is slow, and the control effect is also weakened with the thickness reduction. To solve this problem, rolling mill designers and manufacturers at home and abroad have begun to use variable crown rolls (VC rolls) as backup rolls to eliminate the deviation of the parabolic shape of the plate and greatly improve the shape of the plate. Quality [4].
The VC roller is a combined support roller, which is assembled by a mandrel, a shaft sleeve and a rotary joint. There is a fluid chamber in the central area of ??the roller body between the mandrel and the shaft sleeve, which is filled with high-pressure oil with variable pressure. . The shaft sleeves at both ends of the roll neck are contracted, and the contraction joint is used as an external seal for the internal pressure oil and used for the free slip torque transmission of the roll drive. Its working principle is: the hydraulic oil in the high-pressure hydraulic station is sent to the expanding fluid chamber through the rotary joint through the hydraulic servo control to expand the shaft sleeve, and the uniform mechanical convexity is formed over the full length of the roll body to compensate for the roll produced during work Deflection. Because the VC roller diameter expansion has a linear relationship with the oil pressure in the cavity within a certain range, and can be steplessly adjusted, it can participate in the closed-loop shape control system.
Due to the different thickness of the strip, rolling mill rolling is a process of change from positive roll gap rolling to negative roll gap rolling. For control, it is also a process of combining multiple control methods, mainly including position control, pressure control, and pressure. Compensation control, AGC control, etc.
The speed setting of the rolling mill is set by the main operator on the main console in accordance with the process requirements, and is transmitted to the AGC via the Ethernet, and the AGC is then transmitted to the PLC and each transmission system. The speed setting is based on the main frame as the linear speed reference, and the given value of the speed is given by setting the diameter of the work roll and the reduction ratio of the reduction box. According to the control function, the speed setting has forward and reverse jog settings for fault handling; the threading speed setting is used for threading the rolling mill before production; the rolling line speed setting is used for normal rolling conditions. According to the principle of equal linear speed, it is distributed to each transmission system in the form of speed.
The coiling tension is generated by the dragging of the coiling motor to tighten the strip. Indirect tension control is adopted in the system, and the tension torque generated by the winding tension converted to the motor shaft is equal to the electromagnetic torque of the motor. Linear speed measurement is calculated by reading the pulse encoder on the deflector roller in front of the coiler by the speed regulating device, and is an important variable required for the calculation of the coil diameter.
Modern rolling mills perform full variable programming, and divide the system into rolling mill calibration designated application systems, drive serial port application systems, metering control application systems, thickness and flatness control application systems, and optimization application systems. These programs are processed by RDS (Real-time Data Server), and are used for sequencing roll force cylinders and roll bending control through the designated application system of rolling mill calibration. They are divided into rack calibration program, bounce calibration program, and stand safety monitoring program Etc.; Real-time monitoring of the running status of the rolling mill and the data transmitted by the drive and PLC through the drive serial port application system, and the data is stored in the RDS in order to maintain and optimally control the rolling mill.
