In the manufacturing of specialty filter paper and corrugated board, filtration efficiency, air permeability, strength, and stiffness are core performance indicators. On filter paper production lines, large mirror-finish calender rollers subject the wet paper web to high-temperature, high-pressure precision calendering. This not only significantly improves paper surface smoothness and reduces fiber dusting, but also precisely controls pore structure and air resistance—meeting specific filtration accuracy requirements across diverse fields such as medical, air purification, and fuel filtration. For high-strength corrugated medium paper, heavy-duty steel press rollers, with their extremely high hardness and superior fatigue resistance, deliver stable and powerful linear pressure during the critical dewatering and forming stage. This greatly enhances the ring crush strength and overall physical properties of the base paper.