The working principle of the rewinder and the control process

How the winder works

Before rewinding, the rewinder will first produce the base paper roll from the paper machine with a driving crane on the paper return table, and the paper return rack is equipped with a brake motor (paper roll motor), so that if the paper break occurs when the rewinder is running, the rewinder can quickly brake and stop. A rotary encoder is generally installed on the motor as speed feedback, and a series of calculations are made within the PLC to maintain the paper web tension. When running, the paper web is led out from the exit roller through the guide roller, arc roller, round knife slitting part, guide roller, arc roller, and bottom roller, and finally wound on the paper core between the two bottom rollers; After the front and rear bottom rollers rotate, the paper core rotates by relying on the friction generated by the two bottom rollers and pulls the entire paper web to the winding part. During the operation of the rewinder, the tension of the paper web stretches the paper web, so that it is drawn from the base paper roll

The paper web is wound to the finished paper roll core according to the requirements, so that the rewinder can ensure that there will be no paper breakage under the high-speed operation state.

Rewinder control process analysis

To analyze the rewinder control process, it is first necessary to clarify the quality indicators required by the rewinder for the finished paper roll. The quality indicators of the rewinder control process are mainly reflected in the hardness of the finished paper roll (to meet the requirements of inner tightening and outer looseness), the section of the finished paper roll (the cross-sectional end of the round knife cutting paper should be flat, which is convenient for the reprocessing of the finished paper roll after it appears), the wear degree of the coated whiteboard paper surface (the paper surface and the two bottom rollers should be in contact during rewinding, and the paper surface cannot be overly worn during the rewinding process), and the running speed of the rewinder (in order to keep up with the speed of the base paper produced by the paper machine, the rewinder running speed should be at least 3-5 times faster than the speed of the paper machine).

The hardness of the finished paper roll can be expressed by density, according to the definition of density, it can be seen that the weight of the finished paper roll divided by its volume, if the density is large, it means that the hardness of the paper roll is large; The requirement of inner tightening of the paper roll is to prevent the paper roll from deforming with the increase of volume during the rewinding process, and the outer loosening is when the finished paper roll can maintain a certain elasticity during transportation to prevent it from being damaged; It is also required that the radial hardness of the finished paper roll be evenly distributed. The round knife in the process of cutting the paper web will inevitably form a cut section between the separated paper web, in theory can be cut into a plane, but in the actual process is not easy to do, if the cut is uneven, it will cause the two finished paper rolls separated after rewinding difficult to separate. Coated whiteboard paper is a kind of board paper coated with paint, one side of the paper web is a shiny coating layer, and the coating surface will be in contact with the bottom roller during the rewinding process, so it cannot be over-worn.

In the finished paper roll production process, because the rewinder must stop every time it replaces the base paper roll, and under normal circumstances, a base paper roll in the rewinding process has a paper break and may be divided into several times to use up, the intermediate rewinder must stop for joints or replace the finished paper roll core to start rewinding, these breaks are usually an inevitable process, so to ensure the normal production of finished paper rolls, the rewinder running speed must be 3-5 times faster than the speed of the entire paper machine.