Common Polishing Techniques In Industrial Processing

1.Mechanical polishing Mechanical polishing is a polishing method that removes the polished convex part by cutting and plastic deformation of the material surface to obtain a smooth surface. Generally, oil stone strips, wool wheels, sandpaper, etc. are used, and manual operations are mainly used. Special parts such as rotary bodies For the surface, auxiliary tools such as a turntable can be used, and the method of ultra-fine grinding and polishing can be used if the surface quality is high. Ultra-fine polishing uses a special abrasive tool, which is pressed against the surface of the workpiece to be processed in a polishing liquid containing abrasives for high-speed rotation. The surface roughness of Ra0.008μm can be achieved by using this technology, which is the highest among various polishing methods. Optical lens molds often use this method.

2.Chemical polishing Chemical polishing is to make the microscopic convex part of the surface of the material in the chemical medium dissolve preferentially compared with the concave part, so as to obtain a smooth surface. The main advantage of this method is that it does not require complex 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 fluid. The surface roughness obtained by chemical polishing is generally several 10 μm.

3.Electrolytic polishing The basic principle of electrolytic polishing is the same as that of chemical polishing, that is, to make the surface smooth by selectively dissolving the tiny protrusions on the surface of the material. Compared with chemical polishing, it can eliminate the influence of cathode reaction, and the effect is better.

4.Ultrasonic polishing Put the workpiece into the abrasive suspension and put them together in the ultrasonic field, relying on the oscillation of the ultrasonic wave, the abrasive is ground and polished on the surface of the workpiece. Ultrasonic machining has a small macroscopic force and will not cause deformation of the workpiece, but it is difficult to manufacture and install tooling. Ultrasonic machining can be combined with chemical or electrochemical methods. On the basis of solution corrosion and electrolysis, ultrasonic vibration is applied to stir the solution, so that the dissolved products on the surface of the workpiece are separated, and the corrosion or electrolyte near the surface is uniform; the cavitation effect of ultrasonic waves in the liquid can also inhibit the corrosion process and facilitate surface brightening.

5.Fluid polishing Fluid polishing relies on the high-speed flowing liquid and the abrasive particles carried to scour the surface of the workpiece to achieve the purpose of polishing. Commonly used methods are: abrasive jet processing, liquid jet processing, hydrodynamic grinding, etc. Hydrodynamic grinding is driven by hydraulic pressure, so that the liquid medium carrying abrasive particles flows back and forth across the surface of the workpiece at high speed. The medium is mainly made of a special compound (polymer-like substance) with good flowability under relatively low pressure and mixed with abrasives. The abrasives can be silicon carbide powder.

6.Magnetic grinding and polishing Magnetic grinding and 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, easy control of processing conditions, and good working conditions. With suitable abrasives, the surface roughness can reach Ra0.1μm.