Full definition
A rubber processing operation in which compounded rubber is passed between two or more precision-ground, heated steel rolls rotating at controlled speeds to produce continuous sheets of uniform and precisely controlled thickness (tolerance ±0.05-0.1 mm). A modern calender typically has 3 or 4 rolls in an I, L, Z, or inverted-L configuration, with roll diameters of 300-800 mm and face widths of 1,000-2,500 mm. Key applications: (1) Sheeting — producing rubber sheet of specified thickness (0.5-6 mm) for gaskets, flooring, and general fabrication. (2) Fabric coating (frictioning/skim coating) — applying a thin rubber layer onto textile fabric for conveyor belt plies, hose reinforcement, and diaphragm material. (3) Doubling — combining two or more layers. Process parameters: roll temperature (60-110°C), speed (5-50 m/min), nip gap, and roll speed differential (friction ratio). Calendar lines include let-off reels, pre-warming mills, the calender, cooling drums, and wind-up. Quality control: continuous thickness measurement with beta-ray gauges. Per standard rubber manufacturing practice.