1. Deflection of the longitudinal axis of the calender roll caused by the working line pressure
On the calendering equipment, when the pressure mechanism pressurizes the bearings at both ends of the calender roller, the bottom roller and the top roller will have a large bending deflection due to the unidirectional work line pressure. The deflection value is proportional to the product of the 4th power of the roll surface width and the 1st power of the uniform load. The maximum deflection value in the middle can reach hundreds to thousands of microns, which is tens of times the thickness of ordinary paper. This is the main reason for the uneven distribution of the linear pressure between the rollers and the large changes in the paper's lateral calendering and finishing indexes.
2.roll surface processing form and position error
The calender roller is a large-scale processing part. After the surface of the roller is finely ground, the error of its generatrix can reach 10-40μm, and the radial runout can reach 10-20μm. Compared with the thickness of the calendered paper, it occupies a larger Share.
3.roll surface temperature deformation error
When the calender roll is working, due to heat generation and uneven heat dissipation, the temperature of the roll surface will change in the lateral direction. When the lateral temperature difference of the roll surface is 10℃, the temperature deformation error of the roll surface radius can reach 17.0-45.0 μm, also has a greater impact on the effect of paper calendering and finishing.
4.local extrusion deformation error and uneven wear of the contact surface
Due to the uneven hardness of the roller surface, it can cause local squeeze deformation errors on the contact surface of the calender roller and change the pressure between the rollers. After a period of work, local uneven wear of the roller surface can also occur, which affects the lateral calendering of the paper. Uniformity of finishing.
5. Paper thickness error
The thickness error of the paper before entering the calender can generally reach 5%-10% of its average thickness, which also has a certain influence on the uniform distribution of the linear pressure between the rollers of the calender.
