铝质质料在空气中是极不稳固的，，，容易天生用肉眼也难以识别的氧化膜。。由于大连数控加工铝件加工工艺要领的差别，，，如铸造成型，，，或是由延压板材直接剪切而成，，，或是机械细腻加工成型，，，或是经差别工艺成型后又经热处置惩罚或焊接等，，，工件外貌都会泛起差别状态，，，差别水平的污物或痕迹，，，为此在前处置惩罚工序中必需凭证工件外貌的现真相形选择前处置惩罚的工艺要领。。

Aluminum materials are extremely unstable in air and are prone to forming oxide films that are difficult to identify with the naked eye. Due to the different processing methods of aluminum parts in Dalian CNC machining, such as casting molding, direct cutting from extruded sheet metal, mechanical fine processing molding, or forming through different processes and then heat treatment or welding, the surface of the workpiece will present different states and degrees of dirt or marks. Therefore, in the pre-treatment process, the pre-treatment method must be selected according to the actual situation of the workpiece surface.