Sander is a tool used for surface processing, usually used to remove roughness, defects or old paint on the surface of the workpiece to achieve a smooth, uniform surface effect. It can be applied to a variety of materials, including metal, wood, plastic and glass. The grinding machine is usually driven by an electric motor or gas motor, and is equipped with abrasive tools of different shapes and hardness, which can achieve a variety of processing processes such as rough grinding, medium grinding and fine grinding. Grinding machine is widely used in manufacturing, automotive maintenance, woodworking and home improvement and other fields, is a common surface treatment tool.