How To Prevent White Spots

Aluminum alloy casting has porous structure and high porosity. It contains many types of metallic and non metallic impurities. It is difficult to ensure the quality of anodic oxide film. We can take the following measures to get normal quality of the film and avoid white spot on anodic oxide film after dyed.

1. Density impact method with high voltage and large current. In the initial stage of anodizing people usually use high voltage and large current impact to make them connected together.

2. Grinding method on aluminum alloy casting surface. Grinding can make aluminum fill to the casting pore. It can play an important role on connecting. In fact this method will not be very ideal because that some filling positions will fall off in the process of alkaline etching and anodic oxidation.

3. Peening on the aluminum alloy casting. Generally speaking wall thickness of casting can meet the requirements of pressure during shot peening. Big pressure can be in favor of improve the blasting quality. It can closed pores and cracks through extruded pellets. And also improve the strength and clean on the surface of aluminum alloy casting. As we all know, there is no white spots on the unprocessed casting surface. This is because the casting surface has a dense oxide film.

Casting Application In The Lighting

Casting can form complex shape and  form a beautiful shapes through the NC machining of mold cavity. Casting processing quantity is little, sometimes even without cutting. Casting can also design different wall thickness and structure to satisfy the strength and function of lighting. Certainly we can do the surface treatment according to different installation environment. There is strong corrosion resistance in outdoor environment. Besides using different casting process can not only suitable for small production, but also used for large production. So it can satisfy the demand of various lighting sales. All kinds of casting are widely used in lighting manufacturing industry especially for the manufacture of outdoor lamps.

The most widely used in the lighting is pressure casting, the second is sand casting, metal casting and little investment castings according to classification of the casting method.


Street lamp, advertising lamp, square lamp, part of outdoor wall lamp shell and lamp cover are mostly use aluminum die casting. Garden lamp shell, connectors of wall lamps, most of them are made by aluminum casting and sand casting.
The surface of outdoor lamp is made by aluminum die casting. So we usually use spray and paint surface treatment. The surface of copper and stainless steel castings mainly use polishing or vibration light. Sometimes we can also use paint or spray treatment in order to keep consistent with other parts.