Painting Aondized Aluminum Pedal Enclosure With CNC Machined

The polishing method of aluminum shell castings

During the casting process of aluminum shells, it is easy to produce internal defects such as porosity, shrinkage cavity, and air hole. After machining, the surface dense layer components of these castings with defects are removed, which exposes the internal structural defects. For the automotive aluminum shell with sealing requirements, such as the cylinder block, cylinder head, intake manifold, brake valve body, etc., during the pressure seal test, the existence of defective micropores will lead to the leakage of the sealing medium, resulting in a large number of waste products, and these defects are often found after pressure test after machining, resulting in a serious waste of man hours, raw materials and energy.

To solve the problem of the high scrap rate of an aluminum shell and save the aluminum shell that may be discarded due to the above defects, certain treatment measures should be taken in production. At present, the commonly used technology is infiltration treatment, that is, plugging. The so-called "infiltration" refers to the process technology of penetrating the infiltration agent into the micropores of the aluminum shell under certain conditions, and after curing, connecting the filler infiltrated into the pores with the inner wall of the casting pores, blocking the micropores, so that the parts can meet the conditions of pressurization, seepage prevention, and leakage prevention. Aluminum shell surface technology is rich and diverse, polishing is only one of them, but it is an important process to improve the quality of the aluminum shell. Mastering reasonable polishing methods can improve the quality and performance of aluminum shells, and then improve the quality of aluminum alloy die-casting products.

In addition to conventional mechanical and chemical polishing, there are also electrolytic polishing, ultrasonic polishing, fluid polishing, magnetic abrasive polishing, medium electric spark ultrasonic composite polishing, and other technologies for the polishing of aluminum shell workpiece. The basic principle of electrolytic polishing of aluminum shells is the same as that of chemical polishing, which mainly depends on the selective dissolution of small protrusions on the surface of materials to make the surface smooth. Compared with chemical polishing, it can eliminate the influence of cathode reactions and has a better effect.

The ultrasonic polishing of aluminum shell is a processing method that uses the tool section for ultrasonic vibration and polishes brittle and hard materials through abrasive suspension. The workpiece is put into the abrasive suspension and placed in the ultrasonic field together. Relying on the oscillation of ultrasonic, the abrasive is ground and polished on the surface of the workpiece.

The fluid polishing technology of the aluminum shell needs to rely on the flowing liquid and its abrasive particles to wash the workpiece surface to achieve the purpose of polishing. Hydrodynamic grinding is driven by hydraulic pressure. The medium is mainly made of special compounds with good flowability under low pressure and mixed with abrasive. The abrasive can be silicon carbide powder.

Magnetic abrasive polishing is also one of the polishing technologies involved in aluminum shell processing. Using magnetic abrasive to form an abrasive brush under the action of the magnetic field, the workpiece is ground. This method has high processing efficiency, good quality, and easy control of processing conditions. With proper abrasive, the machined surface roughness can reach ra0.1 μ m.