In order to ensure high adhesion between the skeleton and the rubber, the metal surface needs to be thoroughly cleaned to remove oil and rust, and a new surface is produced. Commonly used methods include chemical treatment (acid-base treatment), mechanical grinding or sand blasting, solvent treatment and copper plating. The solvent treatment method is inferior, but it is often used as an indispensable auxiliary method. For different types of metals and skeletons with different shapes and structures, the surface treatment methods are not identical. Metal surface treatment is nothing more than cleaning, degreasing, mechanical treatment and chemical treatment. Usually used in combination: degreasing → mechanical treatment → degreasing; degreasing → chemical treatment; degreasing → mechanical treatment → degreasing → chemical treatment.