Both CNC and polishing are "cutting" the surface of the wheel hub to achieve a flat effect.But the difference lies in the scale range. If a CNC lathe can be processed at 0.1~1mm, then polishing is processed at 0.01~0.05.Because they have different depths of "knife marks" on the wheels, they have different flatness and different reflective effects. However, due to the insufficient processing depth of the polishing method, the workpiece must be processed to a certain flatness difference by a lathe before the polishing process can be done. So it stands to reason that the wheels will definitely be polished after they have been CNC refined. Otherwise, the rough turning knife marks and some bumps on the wheel rim will appear more obvious after polishing. Generally speaking, the brightness of polishing is higher than that of CNC turning. In addition, if it is a shallow scratch, if it does not penetrate the paint coating, just repair the paint. If the paint is penetrated, as mentioned earlier, polishing has almost no correction effect on the scratches, and it will only brighten the scratches, making them more obvious. It still has to be polished after the car.