Various carbon graphite products, although they have a certain shape and size after forming, undergo expansion and contraction, deformation and bending, collision or corner dropping during the process of roasting, impregnation, and graphitization treatment from the pressed blank to the graphitized blank. The surface adheres to some fillers and insulation materials, resulting in roughness and unevenness. Their shape and size change to a certain extent, and they cannot achieve the shape of the product during use, Due to strict requirements for size and surface roughness, it cannot be used without mechanical processing. In addition, some products have complex structures and shapes that cannot be directly produced by forming methods, such as metal continuous casting and rolling graphite crystallizers, electric spark machining graphite molds, carbide sintering graphite boats, discs, and other special graphite products. Some products require interconnection when used, such as the connection threads between steel electrodes and joints, the installation of brush braids, and the dovetail grooves of carbon blocks, all of which require mechanical processing to be manufactured. Therefore, the purpose of mechanical processing of carbon graphite products is to use the products to meet the specified shape, size, surface roughness, and other special requirements during use.

Although most carbon graphite products require mechanical processing, some products can also be used without mechanical processing, such as pre baked anodes for aluminum smelting, brushes with brush braids, some small brushes and electrical contacts, and some resin type sealing rings and shaft sleeves.