Research on Laser Degreasing
Currently, the application scenarios for laser degreasing are quite complex, involving various materials and oil stains. Since different substrates and oil stains have different absorption rates for lasers, it is necessary to determine the cleaning and damage thresholds for different materials in advance. This is crucial for determining the laser process. Related experimental results show that for carbon steel, the cleaning threshold is (160±10) mJ/cm² and the damage threshold is (410±120) mJ/cm². For stainless steel, the cleaning threshold is (130±10) mJ/cm² and the damage threshold is (420±20) mJ/cm². For copper, because its reflectivity to 1064 nm laser (R=0.85) is much higher than that of carbon steel (R=0.47) and stainless steel (R=0.68), its cleaning and damage thresholds are significantly higher than those of carbon steel and stainless steel, at (1500±100) mJ/cm² and (3200±200) mJ/cm², respectively.A laser degreasing model based on a blasting mechanism was established using COMSOL Multiphysics finite element analysis software. The effects of single-pulse energy on the substrate surface temperature and evaporation migration rate were analyzed, and the cleaning effect on oil contaminants of different thicknesses under different single-pulse energies was simulated. Simulation results show that the maximum temperature rise of the substrate surface is positively correlated with the single-pulse energy; the maximum temperature rise increases with increasing single-pulse energy. The evaporation migration rate of the substrate surface is affected by temperature; the higher the single-pulse energy, the higher the substrate temperature and the larger the effective evaporation area. Regarding the cleaning effect on oil contaminants of different thicknesses under different single-pulse energies, when the single-pulse energy is 1.1 mJ, the maximum effective oil contaminant thickness is 70 μm–100 μm; when the single-pulse energy is 2.0 mJ, the maximum effective oil contaminant thickness is 200 μm–250 μm.
[Image 4: Simulation of cleaning effect on oil contaminants of different thicknesses under different single-pulse energies]
