Study on damage threshold and cleaning threshold of laser cleaning aluminum alloy oxide film

Aluminum alloy is widely used to make building panels, doors and windows, curtain walls, automobile decorative parts and aircraft skin due to its corrosion, surface treatment, beauty and durability. There is usually a dense oxide film on the surface of aluminum alloy. The oxide film has many pores, and the pore size becomes larger from the inside to the outside. It has good adsorption capacity and strong adhesion with the substrate. Therefore, it is necessary to pretreat and clean the oxide film of aluminum alloy. Compared with the traditional cleaning method, laser cleaning is an advanced environmental protection cleaning technology. Laser cleaning method has the characteristics of less environmental pollution, no contact, less wear on the substrate, high flexibility and stability, which can realize automatic cleaning, wide application range and good cleaning effect. But the key problem of cleaning is to determine the laser cleaning threshold and damage threshold. Firstly, the experiment of laser cleaning aluminum alloy oxide film was simply carried out, and the cleaning threshold and damage threshold were roughly determined by the morphology characteristics. In the theoretical part, the cleaning threshold is obtained by heat conduction model and numerical calculation analysis. Finally, it is found that the theoretical calculation results are consistent with the experimental results.