The principle of shot blasting is to use the motor to drive the impeller body to rotate (directly or driven by V-belt), and by the action of centrifugal force, throw the shot with diameter of about 0.2 ~ 3.0 (including cast steel shot, steel wire cut shot, stainless steel shot and other different types) to the surface of the workpiece. Dalian sand blasting and shot blasting can make the surface of the workpiece reach a certain roughness, make the workpiece beautiful, or change the welding tensile stress of the workpiece to compressive stress, Improve the service life of the workpiece. By improving the surface roughness of the workpiece, the paint film adhesion of the subsequent painting of the workpiece is also improved. Shot blasting is almost used in most fields of machinery, such as shipbuilding, auto parts, aircraft parts, gun and tank surface, bridge, steel structure, glass, steel plate profile, anti-corrosion of inner and outer walls of pipeline and even road surface.