Optimization And Research Of Support Adaptive Algorithms Based On STL Model

STL file is the data file of CAD model entity data processed by triangular meshing.It consists of a number of triangular patches to approximate the original CAD model,which becomes the standard format for data conversion between the CAD system and the rapid prototyping system.In this paper,the STL model is studied and optimized in the aspects of support structure stability,peeling easily,consumables and time-consuming in order to improve the model forming efficiency and surface accuracy,and save printing materials and forming time.Firstly,data topology reconstruction algorithm.STL files store a large number of discrete,independent and easy-to-operate data,which results in a large number of redundant data reading and the lack of adjacency relationship.By analyzing the advantages and disadvantages of the data correlation algorithm,hash algorithm,half-edge structure and AVL tree-based auxiliary structure topology reconstruction algorithm,the data topology reconstruction algorithm based on saturated linked list is adopted.The vertices of triangular blocks are stored in the list,redundant vertices are removed,vertex sub-list and adjacent relations are created,saturated vertices of empty sub-list are identified,and data comparison is ignored.A slightly marked vertex.The algorithm reduces the range of vertex comparison,saves unnecessary comparison time and improves the efficiency of the algorithm.Aiming at the influencing factors of the model in the forming process,the objective function is to save the printing material for external support effectively,reduce the attachment area of support and improve the surface accuracy of the model.The optimum solution is obtained and the optimum forming angle is obtained,so as to improve the quality of the model and reduce the consumption of printing material.Secondly,the hierarchical algorithm of the model is analyzed.The advantages and disadvantages of the slicing method based on geometric topological information,the slicing method based on position information of triangular patches and the slicing method based on local geometric topological information are analyzed.An adaptive hierarchical method based on step effect is proposed,and the redundant data generated in the hierarchical process is optimized.The algorithm calculates the stepped height according to the stepped effect of the model,and calculates the adaptive layer thickness of the model by the stepped height and the angle between the normal vector of triangular patches and the direction of layering.The algorithm can lay various STL models and has the advantages of reliability,stability and high efficiency.Finally,a discrete adaptive tree-shaped support structure algorithm is proposed.By identifying suspension edges,suspension points and supporting faces,the saturated vertices are deleted,and the regions to be supported are quickly integrated,and data optimization and boundary contour extraction are carried out.The support region is optimized by discrete adaptive sampling method to obtain the support vertex.At the same time,the support structure is designed,and the column support and tree support are added.In this paper,the tree support structure is mainly studied and the branching is optimized.The top of the support structure is subtracted to reduce the contact area between the support and the surface of the model,which is convenient for peeling after shaping.Through the adaptive optimization of the layer thickness,adaptive layering can be carried out for different parts of the same STL model,which not only reduces the distortion of the solid model under the ladder effect,but also improves the forming accuracy of the model surface.The adaptive optimization of sampling spacing can reduce the number and cost of support,and improve the difficulty of support structure peeling by selecting and optimizing the support vertex according to the adaptability of resampling spacing in the process of support structure generation for different STL models.