The Research Of 3D Printing For Large-scale Complex Topographic Map

Topographic maps are closely related to people's lives.Since the characteristics of topography and landform affect people's daily lives,the development and distribution of street neighborhoods,and the requirements and demands for geographical information from all walks of life are constantly improving.Therefore,the three-dimensional geometric modeling of topographic maps and the three-dimensional solid manufacturing have become a trend and direction of development,and an urgent issue to be solved.The emergence of 3D printing technology provides a new approach to manufacture 3D solid model of topographic map.Based on the selective laser sintering 3D printing technology,this paper systematically establishes the technical scheme of 3D digital manufacturing of topographic maps and solves the topographic map 3D solid model including the acquisition of topographic map 3D geometric model to the 3D printing and manufacturing of topographic map 3D solid model,solid model to the 3D printing and manufacturing of topographic map 3D solid model.With this technology we have successively solved the difficulty of docking solid manufacturing technology and additive manufacturing technologies,implemented 3D printing of complex large-scale and topographic maps,Meanwhile,in the process,the technology and model have been optimized.And 3D detection and evaluation of dimensional accuracy of terrain map solid models have been achieved.In this paper,the equidistant scattering algorithm and Delaunay triangulation algorithm were used to convert a large amount of terrain linear data into STL grid data at one time.Finally,a three-dimensional model of topographic map STL was obtained through simple software processing,which can be realized during data processing.The parameters can be real-timely adjusted to controls the accuracy of the geographic model according to the design requirements.DSC differential thermal analysis and infrared spectrum analysis techniques were used to obtain the DSC curves and melting temperature parameters of the powder-molded material coating resin.Then,the laser printing process parameters and post-treatment curing process parameters were reasonably determined.A shell-type 3D printing process scheme was proposed to reduce the weight of the sand mold and achieve lightweight manufacturing of the topographic map three-dimensional solid model.In the post-processing mode,the flame heating method is used instead of the traditional oven heating for the large-format sand type,which improves the curing efficiency of the post-treatment and the final strength of the sand mold.With Handscan700 laser scanning equipment,and using reverse engineering technology,3D printed topographic map 3D solid model and flame heating and solidification(enhanced)model are modeled by 3D reverse modeling.The three-dimensional dimensional accuracy of 3D printing solid model,3D geometric model(CAD design model)and of the three-dimensional model before and after curing was compared and analyzed.The results show that the precision of the three-dimensional solid model of the topographic map produced by laser 3D printing is within ±1mm/500 mm and the accuracy of the topographic map three-dimensional solid model before and after the flame curing is within ±0.1mm/500 mm.The printing accuracy is high,and the flame heating posttreatment has little effect on the accuracy of the model.