The paper in the machine direction is not flat or is bent in the direction of single-sided paper or downward in the direction of double-sided paper. Often referred to as "tension warping" or "end-to-end warping."

1, the reason (up tension warping)

Single-sided web tension or tension is too high

Insufficient tension on the duplex web

The running speed of the upper and lower conveyor on the double-sided machine is inconsis

Measure

To ensure that no positive warpage occurs, reduce the wrap angle on the single-sided web, reduce the tension on the single-sided paper, reduce the brake on the single-sided paper preheater, and increase the brake on the double-sided web preheater. To ensure that there is no positive warpage under the premise of increasing the angle of the double-sided paper preheater to check the conveyor belt speed, pull the drive pulley so that the speed of the upper and lower conveyor belt is consistent

2, the reason (down tension deformation)

Refer to the above analysis and take the opposite measure.

Measure