a.the welded parts are rough, so they must first be polished and slag removed,

b.there are rust spots and oil stains on the metal surface, phosphating treatment is required to achieve the purpose of removing oil and rust,

c.because the surface is relatively rough, putty ash should be scraped on the surface and polished smoothly,

d.finally, high-temperature electrostatic spray treatment is carried out to form paint on the surface. This process is similar to ironing the sewn clothes flat and cutting off the excess stitches.