Study Of Laser Precision Etching Textures On Large-Scale Three-Dimensional Parts

With the rapid development of modern industry, it is necessary to fabricate three-dimensional micro-structural textures on the surface of large complex surface parts such as airplane wings and other marine propellers so as to achieve the special surface properties such as microwave emission, conduction, wear and corrosion, etc. The traditional way is machining the textures with the five-axis CNC machine tools for precision milling/grinding. This method, however, is not only difficult to take account of both high precision and efficiency processing, but also impossible to process flexible materials.In this dissertation, a novel laser projection etching technique on complex surfaces was introduced in connection with the features of complex surfaces, according to the principle of light parallel projection and by means of the special property of the depth of focus of focused laser beam. A two-dimensional laser galvanometer combied with the three-dimensional working table, defined as "3+2" axis of UV laser processing system, was established to etch the surface of micro-region. With the help of the movement of three-axis CNC machine table, the processing of the three-dimensional micro-structural patterns on the surface of large complex surface parts can be completed successfully.The principle of the feasibility, processing steps and processing characteristics of this novel laser projection etching technique on the surface of complex surfaces was introduced. In addition, the source of systematic error, models, comprehensive error assessment and error control methods in the processing were analyzed. Finally the influence of laser processing parameters on the etching precision and quality was studied by means of experiments.The results showed that the theoretical processing error might reach a few microns and comprehensive error assessment is less than 10μm with the help of"3+2"systems, even though the processing speed reached up to 1000mm/s or more. Morevoer, the plane angle, a small grid size, laser power, repetition rate, scanning speed and the number of processing on the line width, length, depth and morphology were investigated.The experimental results demonstrated that with this new technology of laser projection etching complex textures could be etched on complex surfaces efficiently and precisely. As this technology has a lot of advantages such as high precision, processing efficiency, simple equipment, material flexibility and low processing cost, which is an important direction of future development of the technology of processing micro-structural textures on the complex surfaces.