An springback compensation method for on-line real-time metal sheet roll bending includes the steps of using multiple rollers to bend a continuous metal sheet of multiple sections having different materials or different thickness respectively; using a first position sensor to individually measure springback angles of the multiple sections of the bent metal sheet, and feeding back to a programmable logic controller; using the programmable controller to control a bending roller to compensate the multiple sections of the bent metal sheet respectively; using a second position sensor to individually measure compensated angles of the multiple sections of the bent metal sheet; and comparing a difference between the compensated angles and standard angles of the multiple sections of the bent metal sheet after compensating bending.

An springback compensation method for on-line real-time metal sheet roll bending includes the steps of using multiple rollers to bend a continuous metal sheet of multiple sections having different materials or different thickness respectively; using a first position sensor to individually measure springback angles of the multiple sections of the bent metal sheet, and feeding back to a programmable logic controller; using the programmable controller to control a bending roller to compensate the multiple sections of the bent metal sheet respectively; using a second position sensor to individually measure compensated angles of the multiple sections of the bent metal sheet; and comparing a difference between the compensated angles and standard angles of the multiple sections of the bent metal sheet after compensating bending.

An evaluation device that determines, based on data acquired by an acquisition device, an error value (PF) relating to the flatness of a strip of a rolling material exiting a roll stand, and supplies the determined error values (PF) to a control device, which takes the error values (PF) into account when determining adjustment variables(S) for flatness control elements of the roll stand. The interaction of the acquisition device, the evaluation device, the control device and the roll stand results in a closed control loop working in real time. In order to determine the particular error value (PF) of the strip, the evaluation device performs a local frequency analysis of the data and determines the particular error value (PF) on the basis of the local frequency analysis.

A measuring assembly with a mechanical excitation device that excites the metal belt of a transport device at an excitation frequency (fA) to produce mechanical vibrations. Analog measurement signals (MA) characterizing the amplitude (A) of the excited mechanical vibrations are detected for corresponding regions of the metal belt using sensor elements. The measurement signals (MA) are digitized with digitization devices and the digitized measurement signals or signals derived therefrom are transmitted from the digitization devices to an evaluation device arranged outside of the measuring assembly as transmitted signals (MA). The sensor elements comprise eddy current sensors. The eddy current sensors, which directly adjoin one another when viewed in the width direction are operated using different operating frequencies (f1, f2, f3). When the sensor elements are viewed as a whole, a plurality of sensor elements are operated using the same operating frequency (f1, f2, f3).

A rolling mill with oil-cooled top and bottom work rolls at the entry side and a water spray header at the exit side of the bottom work roll. Water cooling is used below the pass line, reducing the heat in the mill substantially without the risk of generating drip-related surface defects during rolling. Water cooling can be used on the bottom work roll and a portion of the oil no longer needed to cool the bottom work roll can be diverted to the top work roll. In some cases, the coolant portion of the flatness control can be operated solely through water-cooling the bottom roll.

Systems and methods for improving the flatness of a rolled sheet or strip by the application of differential cooling. A cooling agent can be selectively applied along the width of the strip. More cooling can be applied to the edges of the strip, where tension is greatest, to increase tension at the edges. The strip can be allowed to lengthen at these edges, which can improve flatness. In some embodiments, a closed loop flatness control system is used to measure the flatness of a strip and automatically adjust the differential cooling based on the measurement.

Systems and methods for improving the flatness of a rolled sheet or strip by the application of differential cooling. A cooling agent can be selectively applied along the width of the strip. More cooling can be applied to the edges of the strip, where tension is greatest, to increase tension at the edges. The strip can be allowed to lengthen at these edges, which can improve flatness. In some embodiments, a closed loop flatness control system is used to measure the flatness of a strip and automatically adjust the differential cooling based on the measurement.

A control system employs a model-based multi-variable predictive control for cold rolling mills to improve sheet thickness uniformity to meet or exceed specifications in flatness. Sheet metal thickness and flatness deviations from standard requirements are significantly reduced with attendant improved control accuracy as compared to traditional control approaches that use PID based closed loop controls. The control system is particularly suited for control of 4-hi non-reversible single-stand metal rolling mills. The mill stand has a first work roll and a second work roll respectively positioned between a first back up roll and a second back up roll. A plurality of sensors measures and acquires property data of the sheet of material. A model predictive controller manipulates actuators to regulate thickness and flatness. The controller executes automatic gauge control, which is machine direction metal control, and automatic flatness control, which is cross direction metal sheet control, as metal sheet is rolled.

A control system employs a model-based multi-variable predictive control for cold rolling mills to improve sheet thickness uniformity to meet or exceed specifications in flatness. Sheet metal thickness and flatness deviations from standard requirements are significantly reduced with attendant improved control accuracy as compared to traditional control approaches that use PID based closed loop controls. The control system is particularly suited for control of 4-hi non-reversible single-stand metal rolling mills. The mill stand has a first work roll and a second work roll respectively positioned between a first back up roll and a second back up roll. A plurality of sensors measures and acquires property data of the sheet of material. A model predictive controller manipulates actuators to regulate thickness and flatness. The controller executes automatic gauge control, which is machine direction metal control, and automatic flatness control, which is cross direction metal sheet control, as metal sheet is rolled.

The invention may relate, among other things, to a device for straightening a metal strip having two strip drives which are suitable together to apply tension on the metal strip to straighten the metal strip, wherein at least one of the strip drives is a linear drive, characterized in that the at least one linear drive has a positioning device such that the linear drive can be moved relative to the longitudinal axis of the device.