Research On Slicing Algorithm And Path Planning Method For Biological 3D Printing

Biological 3D printing has an important role and broad development prospects in organ transplantation,drug research and other biomedical fields.Slicing and path planning is an important part of 3D printing technology,but at present slicing software is mostly aimed at 3D printing in manufacturing industry.When applied to biological 3D printing,problems such as surface roughness,feature loss,material waste and poor activity of finished products will appear,which seriously affect the quality,efficiency and economy of printing.Combined with the characteristics of biological 3D printing,this paper studies and optimizes the key algorithms such as slicing and path planning,so as to improve the printing quality and efficiency,and construct the appropriate spatial structure.The main contents of this paper are as follows:Firstly,the format characteristics of STL model file are analyzed,the keywords or bytes are used to identify the normal vector and vertex coordinate data of the model,and the structure of point table and facet table is designed for storage,which provides calculation data for subsequent links.For redundant vertex data in STL file,hash table is used to filter,and hash conflict is reduced by optimizing hash table and hash function.In addition,aiming at the problem that the original model position is not suitable for printing,the adjustment method of model position is studied.Secondly,aiming at the problem that the traditional slicing algorithm can not take into account the printing quality and printing efficiency,an adaptive slicing algorithm is proposed to reduce the step effect and retain the model features.Based on the analysis of step effect and model features,a method to determine the layer thickness is designed by using the inclination angle of triangular facets,the dihedral angle of adjacent triangular facets and the proposed vertex complexity index.For the problem that the feature of the model may be missed when there are uncut triangular facets between the two layers,a correction method of layer thickness is proposed.On the basis of determining the printing thickness and height of each layer,the path is planned according to the characteristics of biological 3D printing.Firstly,the printing area is divided,and the generation methods of contour,filling and supporting area are studied.Then,in order to reduce the empty driving distance in the printing process,ant colony algorithm is used to optimize the order of printing contour.In order to construct a good spatial structure of the model,the linear partition scanning method is used to plan the filling path,and the adjustable printing control parameters and printing mode are designed.Finally,the Gcode and generation method in biological 3D printing are briefly described,and the planned path is transformed into instructions that can be recognized by 3D printer.Lastly,the development of biological 3D printing software and the construction of experimental platform are completed.According to the requirements of 3D printing process,the function modules of printing environment configuration,printing preparation,printing operation and system maintenance are designed in the software.The functions of 3D model input,adaptive slicing,path planning and generation of gcode file are realized.The printing experiment with biological 3D printer proves the effectiveness and practicability of the printing software designed in this paper.