What are the polishing methods commonly used for die casting of aluminum alloys?

1, mechanical polishing

Mechanical polishing is by cutting, material surface plastic deformation to remove the polished convex and get a smooth surface polishing method, generally using oil and stone strips, wool wheels, sandpaper, etc. , to manual operation-oriented, high surface quality requirements can be used ultra-fine research and throwing method. Ultra-fine research throw is the use of special abrasives, in the abrasive-containing research throw, pressed on the aluminum Alloy die castings are processed surface, for high-speed rotational motion. The technology allows for surface roughness of Ra0.008 m, the highest of any polishing method. Optical lens molds often use this method.

2, chemical polishing

Chemical polishing is to allow aluminum alloy die castings in the chemical medium micro-protruding parts of the surface than concave parts of the priority dissolve, so as to obtain a smooth surface. The main advantage of this method is that it does not require complex equipment, can polish the shape of complex aluminum die castings, can polish many aluminum alloy die castings at the same time, high efficiency. The core problem of chemical polishing is the formulation of polishing liquid. The surface roughness obtained by chemical polishing is generally 10 m.

3, electrolytic polishing

The basic principle of electrolytic polishing is the same as chemical polishing, that is, by selectively dissolving the surface of the surface of the small protruding part, so that the surface is smooth. Compared with chemical polishing, the effect of cathodic reaction can be eliminated, and the effect is better. The electrochemical polishing process is divided into two steps:

(1) Macro flattening dissolved products diffused into the electrolyte, aluminum alloy die casting surface geometric rough decline, Ra > 1 m.

(2) The microlight is flat anode polarization, the surface brightness is increased, Ra < 1 m.

4, ultrasonic polishing

The aluminum alloy die casting is placed in the abrasive suspension and placed together in the ultrasonic field, relying on the oscillation of ultrasonic, so that the abrasive is polished on the surface of the aluminum alloy die casting. Ultrasonic processing macro force is small, will not cause aluminum alloy die casting deformation, but the production and installation of workwear is more difficult. Ultrasonic processing can be combined with chemical or electrochemical methods. On the basis of solution corrosion and electrolysis, the ultrasonic vibration stirring solution is applied to dissolution of the surface of the aluminum alloy die casting, corrosion or electrolyte is uniform near the surface, and the hollowing effect of ultrasonic in the liquid can also inhibit the corrosion process and facilitate surface brightening.

5, fluid polishing

Fluid polishing is the purpose of polishing by using high-speed liquid and the grinding particles it carries to wash the surface of aluminum alloy die castings. Common methods are: abrasive injection processing, liquid injection processing, fluid power grinding and so on. Fluid-powered grinding is hydraulically driven, allowing liquid media carrying grinding particles to flow back and forth through the surface of aluminum alloy die castings at high speed. The medium is mainly made of special compounds (polymer-like substances) that flow well under lower pressure and are mixed with abrasives, which can be made of silicon carbide powder.

6, magnetic grinding polishing

Magnetic grinding polishing is the use of magnetic abrasives under the action of magnetic field to form abrasive brush, aluminum alloy die casting grinding processing. This method has high processing efficiency, good quality, easy control of processing conditions and good working conditions. With the right abrasive, the surface roughness can reach Ra0.1 m.