Calendering machines play a vital role in compressing copper or aluminum foil coated on both sides using a rotating pair of rollers. Before compression, the electrode foil undergoes static discharge and is cleaned with brushes or air flow. The material is then compacted between the top and bottom rollers, which apply a precisely defined line pressure. This pressure influences the porosity of the coated material, affecting electrode wetting properties and cell energy density. After calendering, the electrode foil is cleaned again and rewound in a roll-to-roll process. Proper roller cleanliness is essential to prevent foreign particles from contaminating the substrate. Excessive line pressure can cause stress cracks due to material squeezing, making precise control crucial for maintaining quality and performance.