1. Mechanical polishing
Mechanical polishing is a polishing method that removes protrusions on the surface of the workpiece by cutting or plastic deformation of the material surface to obtain a smooth surface. Generally, oil stone sticks, wool wheels, sandpaper, etc. are used. Manual operation is the main method. Those with high surface quality requirements can be used. Super-precision polishing method. Ultra-precision polishing is the use of special abrasive tools, which are pressed against the processed surface of the workpiece in a polishing fluid containing abrasives for high-speed rotation. The surface roughness of Ra0.008 μm can be achieved by using this technology. Optical lens molds often use this method. Mechanical polishing is the main method of mold polishing.
2. Chemical polishing
Chemical polishing is the process of dissolving the microscopically protruding part of the material in a chemical medium preferentially than the concave part, thereby obtaining a smooth surface. The method can polish workpieces with complex shapes, and can polish many workpieces at the same time, with high efficiency. The surface roughness obtained by chemical polishing is generally Ra10 μm.
3. Electrolytic polishing
The basic principle of electrolytic polishing is the same as that of chemical polishing, that is, it relies on the selective dissolution of small protrusions on the surface of the material to make the surface smooth. Compared with chemical polishing, it can eliminate the influence of cathode reaction, and the effect is better.
4. Ultrasonic polishing
Ultrasonic polishing is a processing method that uses the tool section to perform ultrasonic vibration and polishes brittle and hard materials through abrasive suspensions. Put the workpiece in the abrasive suspension and put it together in the ultrasonic field, relying on the vibration of the ultrasonic to make the abrasive polish on the surface of the workpiece. Ultrasonic machining has a small macro force and will not cause deformation of the workpiece, but it is difficult to manufacture and install tooling.
5. Fluid polishing
Fluid polishing relies on flowing liquid and the abrasive particles carried by it to wash the surface of the workpiece to achieve the purpose of polishing. Hydrodynamic grinding is driven by hydraulic pressure. The medium is mainly made of special compounds (polymer-like substances) with good flowability under lower pressure and mixed with abrasives. The abrasives can be made of silicon carbide powder.
6. Magnetic grinding and polishing
Magnetic abrasive polishing is to use magnetic abrasives to form abrasive brushes under the action of a magnetic field to grind the workpiece. This method has high processing efficiency, good quality and easy control of processing conditions. Using suitable abrasives, the processed surface roughness can reach Ra0.1 μm.
7. Electric spark ultrasonic composite polishing
In order to improve the polishing speed of the workpiece with a surface roughness Ra of 1.6 μm or more, ultrasonic and a special high-frequency narrow pulse high-peak current pulse power supply are used for composite polishing. The corrosion of ultrasonic vibration and electric pulse simultaneously acts on the surface of the workpiece, which is rapidly reduced Its surface roughness is very effective in polishing the rough surface of the mold after machining by turning, milling, EDM and wire cutting.