Medium-to-high soft calender with controllable zones in the machine (single nip and double nip)

Performance: Calendering is a process in which the smooth roller surface and the rough paper web surface repeatedly interact after the paper web leaves the drying section. The function of soft calendering is very similar to the principle of ironing clothes with an iron. Paper is obtained by heat and pressure Smoothness, the soft calender replaces the ordinary calender and the super calender is to increase the surface temperature of the roller and the width of the nip to replace the repeated line pressure of multiple rollers to achieve the effect of calendering.

Features: The surface of the hard roll has high hardness and high smoothness. When pressing, the elastic deformation of the soft roll makes the two rolls form a surface contact. The contact surface width of the soft calender can reach 10-25mm, which is 15 times that of the mechanical calender. , the unit pressure is generally 20-40N/mm2, even if the line pressure of the calender is higher, the unit pressure is only 1/2-1/4 of the mechanical calender, because the nip is wider, the paper is pressed As the zone residence time increases, its energy consumption is transferred to the paper in the form of heat, which plasticizes the paper fibers, and the softened fibers are easier to calender and increase the smoothness. The resilience of the soft roll surface material enables the roll surface to adapt to any bad evenness and quantitative changes in the paper sheet, so it can have a more uniform smoothness than ordinary hard calenders, and the thinner area of the paper sheet is in contact with the heating roll Good, at the same time, the thickness will not be greatly reduced in the thick area, so that the smoothness can be increased in the thick and thin areas, the color spots can be eliminated, and the printing performance is greatly improved. Another benefit of soft calendering is that the paper is blackened and the color spots Under the condition that the problem is basically eliminated, the paper sheet can run under the condition of high moisture, which not only helps the calendering of the paper sheet, but also keeps the moisture content of the paper roll at a high level. The temperature of soft calendering, nip pressure, nip width and number of nips all affect the calendering effect.