Basic Research On Laser Processing System For Functional Structure Of Non-developable Surface

tructural functional material is a material with periodic fine structure,which can show special functional properties by changing the size and arrangement of surface structure.It is not only used in electromagnetic field,superhydrophobic function,microfluidic and other small structures,but also suitable for large integral panels of aircraft,fan blades,side panels of ships,radar fairing and other large non-developable surfaces.However,there are few researches on the cross-scale automatic machining of microstructures on non-developable surfaces by laser,and the research on the fabrication of microstructures on different metal surfaces is not systematic enough.In this paper,the characteristics of cross-scale automatic machining of non-developable surfaces are analyzed.Firstly,a five-axis CNC laser machining system is built and the software of structural and functional materials processing system is developed.Then,the algorithm of non-developable surface partition,the algorithm of unit layout design in the region,the algorithm of machining path in the region and the algorithm of inter-region connection are proposed.Next,the factors affecting the element distortion and stitching accuracy of flat and non-developable surfaces are analyzed theoretically and experimentally.Finally,in order to improve the preparation accuracy of functional structures,experiments were carried out on the influence of different laser processing parameters on different materials to achieve the purpose of high-precision cross-scale processing of structural functional materials.The main research contents are as follows:(1)Through the design and construction of five-axis laser machining system and the development of structural and functional material processing system software,the establishment of basic experimental facilities for non-developable surface machining was completed.The results show that the platform built by our research group has high repeatable positioning accuracy for each axis and enlarges the scope of machining space.It can complete the work of graphic design,machining and parameter optimization,and basically realize the laser processing of large-area plane and non-developable surface.(2)By using the principle of laser depth of focus and the method of transforming 3d surface into 2D plane processing,the spherical Angle partition algorithm,rectangular partition and rectangular trapezoidal partition unit layout algorithm,automatic processing path algorithm in the region and the joint movement algorithm between regions are designed.The results show that the spherical Angle partition algorithm can satisfy the condition that the partition plane is in the focal depth range,and the laser spot deformation is smaller during machining.The layout design algorithm of partition units improves the problem of large error in interregional splicing by designing the graphs in the region according to the principle of uniform distribution and calculating the error quantization.Through the design and calculation of the machining path in the region,automatic machining according to the bow path in the region is realized.The interzone convergence motion scheme improves the efficiency of cross-scale machining of non-developable surface and further realizes the cross-scale automatic machining of non-developable surface.(3)By analyzing and correcting the causes of the distortion and splicing error,the element splicing experiment and the automatic processing experiment of the non-developable surface copper-clad cover plate were carried out.The results show that the main factors causing the distortion are the principle error of galvanometer,laser optical path error,processing parameters and defocusing amount.After correction,the main reasons affecting the stitching accuracy are the curvature change of the model,the positioning accuracy of the machined surface and the movement accuracy,and the cross-scale machining accuracy of the non-developable surface is optimized.(4)The effect of different uv laser processing parameters on the line width and groove depth was investigated by preparing micro-groove structures on brass,cemented carbide,1060 aluminum and silver.It is found that the line width and slot depth increase with the decrease of pulse width and repetition frequency and the increase of pulse number per unit length in a certain range,and the line width and slot depth increase with the increase of metal resistivity.Through the above work,the goal of high-precision,cross-scale automatic machining of non-developable surface functional structure is finally realized.