Effects of laser texture process on infrared laser absorptivity of copper surface

In the process of copper parts processing by high power infrared laser, low laser absorptivity of copper surface is an important factor hindering its industrial processing and affecting processing quality. The work aims to improve infrared laser absorptivity of copper surface from less than 10% to over 70% through picosecond laser texture pretreatment. Based on changing of copper surface characteristics, precision & minuteness machining system was used to texturize the groove. Texture characteristics at 20%~50% laser power and 20~90 scanning times were analyzed by confocal microscope and scanning electron microscope. The infrared laser absorptivity of copper surface receiving different textures was tested by reflectivity detector. Compared with the original copper plate, the infrared absorptivity of textured copper surface was greatly improved. The absorptivity of copper surface with cross groove textures was higher than that with parallel groove textures under the same parameters. In the process of 30% laser power and 60 scanning times, the cross groove textures formed showed depth of 44 mm, spacing of 50 mm, surface roughness of 12.15 mm and dip angle of 75°, and infrared laser absorptivity of copper surface was up to 86.95%. Texture depth, surface roughness and oxide are three important factors affecting laser absorptivity. After the three processes of period-ic-microscale textures-phase explosion and particles splashing-formation of black CuO layers, corresponding to three-step ab-sorption of light self-trapping texture-spatter particles on surface-CuO layer, texture technology can improve the infrared laser absorptivity of copper surface by nearly 9 times. © 2018, Chongqing Wujiu Periodicals Press. All rights reserved.