The structure of aluminum parts is loose and has high porosity. To a certain extent, it contains a variety of metallic and non-metallic impurities. The quality of the anodized film is difficult to guarantee. Therefore, in order to obtain the normal quality of the oxide film, aluminum parts need to be White spots appeared after the anodized film was dyed.
Aluminum parts are manufactured using the high-voltage and high-current-density impact method. When used, aluminum parts are subjected to high-voltage and high-current impact in the early stage of anodic oxidation, so that the parts originally divided by impurities are connected into a sheet by high-current impact. The initial voltage of the anodization was adjusted to about 30V, and the current density at this time was about 2 to 2.5A / dm2. After 3 to 5 minutes, it was adjusted back to the normal anodizing voltage, anodized for 50 minutes, and then fully dyed to be satisfactory. Oxide film, white spots basically disappeared.
The disadvantage of aluminum parts is that if there are screw holes in the casting, it may be slightly enlarged. Therefore, it is necessary to control the high current density, high voltage anodizing time, and prevent the temperature of the anodizing solution from rising too quickly; continuous production At this time, cooling measures should be taken for the anodizing solution.
The shot peening method on the surface of aluminum parts uses a round-head hammer to knock before using the shot peening method, so that the gap is closed by tapping to achieve the purpose of connecting into pieces, with significant results. Considering that the efficiency of shot peening will be greatly improved, the effect after anodic oxidation and dyeing is better than the above two methods.