Research On Key Technologies Of Rapid Prototyping For Subdivided Surface Based On Multi-Resolution Mesh Segmentation

Additional material manufacturing technology of rapid prototyping can rapidly produce complex shape parts with different materials,shorten the manufacturing cycle,save materials,reduce costs and enhance the competitive advantage of products.It is especially conducive to the production of complex shape,multi-varieties and small batch parts,and has broad application prospects.At present,most of the processing models used in rapid prototyping manufacturing are STL models which are discrete from NURBS design models,but the process of surface discretization is not only time-consuming,but also has a certain loss of accuracy.Compared with the traditional NURBS modeling method,the subdivision surface modeling method can efficiently construct smooth surfaces with arbitrary topological structure,and its discrete mesh nature can not only achieve the unification of rapid prototyping design model and processing model,but also facilitate the trajectory planning and calculation of rapid prototyping manufacturing.Therefore,subdivision surface modeling method is more suitable for rapid prototyping applications.At present,there are few reports on the research of rapid prototyping technology for subdivision surfaces.This paper takes Catmull-Clark subdivision surface model as the research object,based on the structural characteristics of subdivision mesh topology,achieve piecewise subdivision surface representation,and it is based on multi resolution mesh segmentation technology,research the key technology of subdivision surface rapid prototyping.The main research contents are as follows:(1)Construct rapid prototyping machining model based on Catmull-Clark subdivision surface.This paper describes the geometric and topological rules in Catmull-Clark subdivision model and the cellular data structure is used to realize the piecewise representation of the rapid prototyping model for subdivision surfaces.The paper introduces the characteristics of mesh topology and multi-resolution mesh segmentation technology of Catmull-Clark subdivision surface,builds a rapid prototyping model of subdivision surface which meets the requirements of machining accuracy by subdivision surface limit mesh,it lays a foundation for the following research on key technologies of rapid prototyping of subdivision surface.(2)Research on slicing algorithms for rapid prototyping of Catmull-Clark subdivision surface.Based on the structural characteristics of subdivision mesh topology,combined with multi-resolution mesh segmentation technology and bounding box detection technology,the article proposes the Catmull-Clark subdivision surface rapid prototyping model slicing algorithm,and slicing algorithm is verified by practical examples.It analyses the characteristics of contour data obtained by subdivision surface slicing,and discusses the processing of multi-branch intersection lines by slicing algorithm.(3)Research on path planning of slice contour for rapid prototyping of Catmull-Clark subdivision surface.Based on the normal direction of the limit mesh vertex of subdivision surface,the article realizes the construction of XY two-dimensional isometric model for rapid prototyping of subdivision surface and obtains the contour trajectory of isometric slice.According to the characteristics of Catmull-Clark subdivision surface slice contour data,the article proposes a fast sorting algorithm for subdivision surface slice contour data.It uses bounding box detection technology to detect and process the intra-segment self-intersection and inter-segment intersection interference of subdivision surface slice contour data,and then proposes a fast prototyping algorithm for subdivision surface slice contour trajectory planning.It validates the slice contour trajectory planning algorithm through an example model,and carries out rapid prototyping experiments to verify the practicability and effectiveness of the proposed subdivision surface slicing and trajectory planning algorithm.