The formation of surface oxide film after CNC machining of aluminum alloy is a complex process, involving many factors, such as alloy composition, surface treatment process, environmental conditions and so on. Generally speaking, aluminum alloy will form an oxide film on the surface after machining, and the electrical conductivity of this oxide film will be affected to a certain extent.

The oxide film of aluminum alloy is usually formed by the reaction between aluminum, oxygen and other alloying elements. The thickness and composition of this oxide film will change with time and environmental conditions. Under certain conditions, such as high temperature, high humidity or polluted environment, the thickness of the oxide film will increase, and the electrical conductivity may be further reduced.

To determine the duration during which the electrical conductivity of the oxide film on the surface of the aluminum alloy after CNC machining is affected, several factors need to be considered. For example, the type of aluminum alloy, the purity of the alloy, the surface treatment process, the treatment method after machining, and the environmental conditions. These factors will affect the formation rate and composition of the oxide film, and thus they will affect its conductivity.

Specific analysis is required for the formation time and electrical conductivity of the oxide film on the surface of specific kinds of aluminum alloy after CNC machining. In practical applications, if it is necessary to ensure the electrical conductivity of the aluminum alloy surface, appropriate surface treatment processes can be used, such as coating treatment or anodizing. These treatments can form a protective layer with good electrical conductivity on the surface of the aluminum alloy to maintain the stability and durability of its electrical conductivity.

In a word, the formation of oxide film on the surface of aluminum alloy after CNC machining is a complex process, and its electrical conductivity is affected by many factors. To ensure the electrical conductivity of the aluminum alloy surface, appropriate surface treatment processes can be used to protect the surface to maintain its good electrical conductivity.