Mechanical polishing
Mechanical polishing is a polishing method that obtains a smooth surface by cutting and plastic deformation of the surface of the material to remove the convex parts after polishing. Generally, you use whetstone strips, wool wheels, sandpaper, etc., mainly manual operation. Special parts such as the surface of the rotating body can be polished. Using auxiliary tools such as turntables, ultra-precise polishing methods can be used for high surface quality requirements. The ultra-precise grinding polishing adopts a special grinding tool. In the grinding polishing liquid containing abrasives, it is pressed against the surface of the workpiece to be processed for high-speed rotation. Using this technology can achieve a surface roughness of Ra0.008μm, which is the highest among various polishing methods. This method is often used in optical lens molds.
Chemical polishing
Chemical polishing is to make the surface of the material microscopically convex in the chemical medium dissolve preferentially than the concave part, so as to obtain a smooth surface. The main advantage of this method is that it does not require complicated equipment, can polish workpieces with complex shapes, and can polish many workpieces at the same time, with high efficiency. The core problem of chemical polishing is the preparation of polishing liquid. The surface roughness obtained by chemical polishing is generally several 10 μm.
Electrolytic polishing
The basic principle of electrolytic polishing is the same as chemical polishing, that is, the surface is smooth by selectively dissolving the tiny protruding parts on the surface of the material. Compared with chemical polishing, the effect of the cathode reaction can be eliminated, and the effect is better. The electrochemical polishing process is divided into two steps: (1) Macro leveling The dissolved product diffuses into the electrolyte, and the surface roughness of the material decreases, Ra> 1 μm. ⑵Low light leveling Anodized, surface brightness improved, Ra <1μm.
Ultrasonic polishing
The workpiece is placed in an abrasive suspension and placed in an ultrasonic field together, and the abrasive is ground and polished on the surface of the workpiece by the ultrasonic vibration. Ultrasonic machining has a small macro force and does not cause workpiece deformation, but tooling production and installation are difficult. Ultrasonic processing can be combined with chemical or electrochemical methods. On the basis of solution corrosion and electrolysis, ultrasonic vibration is applied to stir the solution to dissolve the dissolved product on the surface of the workpiece, and the corrosion or electrolyte near the surface is uniform; the cavitation of ultrasonic waves in the liquid can also suppress the corrosion process and facilitate the surface brightening.