Mechanical polishing (also known as physical polishing) is to rely on cutting, plastic deformation of the surface of the material to be polished after the removal of the convex part of the polishing method to get a smooth surface, the general use of oleander, wool wheel, sandpaper, etc., mainly hand-operated, special parts, such as rotating body surface, the use of rotary and other aids, the surface quality of the surface of the requirements of the high can be used to ultra-precision research and polishing methods. The surface quality requirement is high, the method of ultra-precision grinding and polishing can be used. Ultra-precision grinding and polishing is the use of special abrasives, containing abrasives in the research and polishing liquid, tightly pressed on the surface of the workpiece being processed, for high-speed rotary movement. With this technique, a surface roughness of Ra0.008 μ m can be achieved, which is the highest among various polishing methods. Optical lens molds often use this method.
2, chemical polishing
Chemical polishing (also known as corrosion polishing) is to let the material in the chemical medium of the surface microscopic convex part of the concave part of the preferential dissolution, so as to get a smooth surface. The main advantage of this method is that it does not require complex equipment, can polish complex shaped workpieces, can polish many workpieces at the same time, and high efficiency. The core problem of chemical polishing is the preparation of polishing solution. The surface roughness obtained by chemical polishing is generally a few 10 μ m .
3, electrolytic polishing
Electrolytic polishing of the same basic principles of chemical polishing, that is, by selective dissolution of the material surface of the tiny protruding parts, so that the surface is smooth. Compared with chemical polishing, can eliminate the influence of cathodic reaction, the effect is better. Electrochemical polishing process is divided into two steps:
(1) macroscopic leveling dissolution products to the electrolyte diffusion, the material surface geometric roughness down, Ra > 1 μ m.
(2) Microlithography Anodic polarization, surface brightness increases, Ra < 1 μm.
4, ultrasonic polishing
The workpiece is put into the abrasive suspension and placed in the ultrasonic field together, relying on the ultrasonic oscillation, so that the abrasive material on the surface of the workpiece grinding and polishing. Ultrasonic machining macro force is small, will not cause deformation of the workpiece, but the production and installation of tooling is more difficult. Ultrasonic processing can be combined with chemical or electrochemical methods. On the basis of solution corrosion, electrolysis, and then apply ultrasonic vibration stirring solution, so that the surface of the workpiece dissolution product detachment, the surface near the corrosion or electrolyte uniformity; ultrasonic cavitation in the liquid is also able to inhibit the corrosion process, and conducive to the surface brightening.
5 fluid polishing fluid polishing is to rely on the high-speed flow of liquid and its carrying abrasive particles flushing the surface of the workpiece to achieve the purpose of polishing. Commonly used methods are: abrasive jet processing, liquid jet processing, fluid power grinding. Fluid power grinding is driven by hydraulic pressure, so that the liquid media carrying abrasive particles of high-speed reciprocating flow over the surface of the workpiece. The media is mainly used in the lower pressure flow through the good special compounds (polymer-like substances) and mixed with abrasives made of abrasive can be used in silicon carbide powder.
6, magnetic grinding and polishing
Magnetic grinding and polishing is the use of magnetic abrasives in the magnetic field under the action of the formation of abrasive brushes, grinding and processing of the workpiece. This method of processing efficiency, good quality, easy to control the processing conditions, good working conditions. Using suitable abrasives, the surface roughness can reach Ra0.1 μ m . Polishing said in plastic mold processing is very different from the surface polishing required in other industries, strictly speaking, the polishing of molds should be called mirror processing. It not only has high requirements for the polishing itself but also has high standards for surface flatness, smoothness and geometric accuracy. Surface polishing is generally only required to obtain a bright surface.