Research On Five-axis Single-point Color Printing Technology And Equipment For Freeform Surface

With the increasing demand of color products,great progress has been made in computer three-dimensional color modeling technology and plane printing.However,three-dimensional color printing technology is still far behind the two technologies.There is no unified definition or concept of three-dimensional printing in the industry,and there is no mature theoretical system to support it.In this paper,a five-axis single-point color printing technology for free-form surface is presented,including design of printing system,design of printing mode,research of printing path planning,research of theoretical printing point adaptive planning and printing experiment.1.Designed the 3D printing system.Based on the three-axis fused deposition printing platform,a five-axis single-point printing equipment is designed,which enables the printing system to adjust the relative pose of workpiece and the platform to realize the spatial normal printing.A single-point color nozzle and a single-point spatial printing scheme are designed.Based on the platform,the control system and the control model of the color nozzle are designed,and the control code form of the system is defined.2.Designed the path planning of the five-axis single-point color printing.The VRML file is used as the loading data of the path planning,and a path planning algorithm based on the adaptive filling of theoretical printing point is introduced,which means that theoretical printing points would be arranged tightly and adaptively on surface.And then the algorithm for calculating the transformation of theoretical printing points pose and color information is introduced.Finally,sorting Output algorithms of theoretical printing points is introduced to form the final printing path.3.The adaptive filling algorithm based on section method is designed.Firstly,an algorithm for generating slice contour with variable thickness is designed.Then,based on the slice contour obtained by the section method,an adaptive filling algorithm of theoretical printing points is designed through the Partition Calculation Point and the Theoretical Filling Area.4.The path planning algorithm based on geodesic offset method is designed.The generation of offset contours based on triangular mesh surface is emphasized.The geodesic offset method based on discrete points is introduced.The interference judgment method based on sampling point trajectory is designed to deal with the local and global self-intersection problems in offset process,and the interpolation connection algorithm is designed to form the final offset curve.5.Experiments of five-axis single-point color printing were carried out.Two kinds of printing modes were designed.One is printing experiments based on the surface of formed products,the other is integrated manufacturing with FDM 3D printing technology to form color workpieces.Finally,for different surfaces,experiments and comparisons of two theoretical printing point planning algorithms were done.