Several polishing methods of aluminum alloy die casting
1. Mechanical polishing.
Mechanical polishing of aluminum alloy die-casting is a polishing method to obtain a smooth surface by cutting and plastic deformation of the material surface, removing the raised parts after polishing. Generally, it is mainly manual operation, and for those with high surface quality requirements, it can adopt the ultra precision polishing method. The ultra precision polishing is to use a special abrasive tool, which is pressed in the polishing solution containing abrasives High speed rotation is carried out on the processing surface of aluminum alloy die castings p>
2. Chemical polishing p>
Chemical polishing of aluminum alloy die casting is to make the micro convex part of the aluminum alloy die casting sheet surface dissolve preferentially in the chemical medium than the concave part, so as to obtain a smooth surface. The main advantage of this method is that complex aluminum alloy die castings can be polished without complex equipment, and multiple aluminum alloy die castings can be polished at the same time, with high efficiency. The core problem of chemical polishing is the preparation of polishing solution, and the surface roughness obtained by chemical polishing is generally 10 μ m。 p>
3. Electrolytic polishing p>
The basic principle of electrolytic polishing for aluminum alloy die casting is the same as that of chemical polishing, that is, by selectively dissolving the small protrusions on the surface of the material, the surface becomes smooth. Compared with chemical polishing, it can eliminate the influence of cathodic reaction, and the effect is better p>
4. Ultrasonic polishing p>
Put the aluminum alloy die casting parts into the abrasive suspension, and put them into the ultrasonic field together. Use the ultrasonic vibration to grind and polish the abrasive on the surface of the aluminum alloy die casting parts. The ultrasonic machining has small macro force, which will not cause deformation of the aluminum alloy die casting parts, but it is difficult to manufacture and install the tooling. Ultrasonic machining can be combined with chemical or electrochemical methods. On the basis of solution corrosion and electrolysis, ultrasonic vibration is used to stir the solution to separate the dissolved products on the surface of aluminum alloy die casting parts. The corrosion or electrolyte near the surface is uniform. The cavitation effect of ultrasonic in the liquid can also inhibit the corrosion process, which is conducive to surface brightening p>
5. Fluid polishing p>
Fluid polishing of aluminum alloy die casting relies on high-speed fluid and its abrasive particles to wash the surface of aluminum alloy die casting parts to achieve the purpose of polishing. Common methods include abrasive jet machining, liquid jet machining, hydrodynamic grinding, etc. Hydrodynamic grinding is driven by hydraulic pressure to make the liquid medium carrying abrasive particles flow back and forth at high speed on the surface of aluminum alloy die-casting parts. The medium is mainly composed of special compounds (polymer like substances) with good fluidity under low pressure and abrasives, which can be silicon carbide powder p>
6. Magnetic grinding and polishing p>
Magnetic abrasive polishing is to use magnetic abrasive to form abrasive brush under the action of magnetic field to grind aluminum alloy die-casting parts. This method has high processing efficiency, good quality, easy control of processing conditions and good working conditions. The surface roughness can reach 0.1 with proper abrasive μ m..