Scanning Strategy Of Multi-mirror 3D Printing Platform And Software System Realization

Selective laser melting(SLM)technology is a new additive manufacturing technology which use high energy density laser to melt the mental powder,according to the preset path,and then cooled and solidified.The rapid development of this technology is due to the quick prototyping of complex metal parts with good mechanical properties and high density.However,there are still some defects in this technology,for example,it is difficult to form parts with large size,and there are residual stress and large degree of warping deformation in the parts.Therefore,based on the visualization of slice files,a path planning algorithm suitable for multi-mirror 3D printing platform is designed,and the advantages of scanning strategy of path planning compared with scanning strategy of source file are verified by numerical simulation.The main research contents are as follows:(1)Data processing of slice file and system implementation.The data processing system of multi-mirror 3D printing platform is realized by the mixed programming method of Visual C++ and MATLAB,combined with the scientific methodology of software engineering.Its functions include parsing,reading,visualization in multi-mode of AFF slice files.In the process of visualization,it is found that the scanning lines in the source file are all long straight lines,which will lead to a high level of residual stress in the molded parts.Therefore,the interface is reserved for the path planning module in the software system design.(2)Design and implementation of path planning algorithm.Based on the common scanning strategy and the structural characteristics of multi-mirror 3D printing platform,a new path planning algorithm is designed.The intra-layer scanning strategy is partitioned spiral scanning,which ensures that the scanning lines in adjacent partitions are orthogonal,and adds end-to-end transition lines to reduce idle travel.Considering the influence of splicing area on the performance of molded parts,the setting of inter-layer scanning strategy ensures that the center point of the area periodically shifts with the superposition of layers to realize inter-layer overlap.In order to verify the advantages of path planning algorithm,two scanning strategies will be compared based on numerical simulation.(3)Temperature field simulation of SLM process.Based on ANSYS finite element software,the SLM multi-layer forming model is established,and the temperature field distribution of single-layer and multi-layer forming parts under the scanning strategy of source file and the scanning strategy of path planning is compared and analyzed.The center points of each layer are selected as sampling nodes,and the thermal cycle temperature curves of each node are studied.The experimental results shows that the phenomenon of fast cooling and fast heating is reduced under the scanning strategy of path planning,which is helpful to avoid large temperature gradient.(4)Stress field simulation of SLM process.Based on the simulation results of temperature field,the stress field simulation of forming parts under two scanning strategies is completed by using sequential coupling analysis method,and the stress field distribution and warping deformation degree are compared and analyzed.The experimental results show that the scanning strategy of path planning is better than the scanning strategy of source file,in terms of the stress value,the stress fluctuation degree on the sampling path and the maximum warping deformation,which agrees with the temperature field analysis results and verifies the advantages of the path planning algorithm.