In general, an important way to improve the surface quality of aluminum castings is by electropolishing. Electropolishing means that the surface of the casting is changed by electrolysis so that a substance called an oxide film is formed on the surface of the aluminum casting.
Overall: the use of electrolytically polished aluminum castings has considerable surface variations. For example, there are obvious enhancements in the color of the surface, the degree of corrosion resistance, the degree of wear, and the hardness; of course, the most important thing is the protection of the metal surface.
It has also been said that anodizing will also achieve the effects we have mentioned above.
Therefore, here is a point: since the raw material of the cast aluminum casting contains a relatively complicated alloy composition which is not easy to distinguish, resulting in the difference in the quality and quality of the oxide layer, and these aggregation on the surface of the alloy not only result in a thin surface of the aluminum casting. Unevenness is accompanied by other serious hazards. In the face of such a situation, we not only delayed the production time, but also tried to remedy other methods, which took time and effort.
There is a case where the anodized film is dyed after the aluminum casting, and its surface layer is particularly prone to white spots. This situation is generally due to the coexistence of different metals and many impurities that are not metals, and is caused by various interventions such as loose structure and high porosity. Need to explain, the appearance of white spots, the impact on quality is very large. To improve these situations, three methods of density impact, sanding, and sanding are used.
Of course, another method is to use the impact of high voltage and high current to make the structure that was originally divided by impurities become one piece under the intervention of large current, which effectively avoids the bad phenomenon of casting surface. However, it is especially reminded that it should be used in the oxidation of castings. Another point is that if the surface of the aluminum casting is directly polished, the polished aluminum will completely fill the entire aluminum casting surface.
Similarly, the principle of shot peening performed on the surface of an aluminum casting is the same. The method is to hit the workpiece with a suitable tool such as a round hammer before shot peening, so that the original gap will close and thus be linked into pieces, thus improving the quality of the oxide film.