Reseach And Application On The Algorithm Of NC Tool Path Generation And Manufacturing Simulation For Triangular Meshing Subdivision Surface Model

Since there are some shortcomings in the algorithm of NC tool path generation and manufacturing simulation for triangular region surface, several kinds of problems such as the index mechanism of triangular meshing subdivision surface, computing and optimization of NC tool path, the construction of blank model for simulation and computing intersection for swept surface of milling tool are researched mostly. The achievements and innovation of this article are as fellows:(1) Through analyzing the principle of space index construction R*-tree thoroughly, its advantages and limitations for indexing discrete data object were reasoned. The constructing method of R*S-tree was put forward, and the circumscribing sphere radius, increment, overlapping of node MBR were regarded as its best judging target for node division solving the limitation of R*-tree. Forcible re-inserting algorithm was proposed to adjust the new inserted node into the MBR of its parental node. The R*S-tree index mechanism, which discrete data can reduce the dead zone of node remarkably, improve inquiring efficiency, extend R*-tree index mechanism and has stronger suitability for discrete data, applied effective index construction for triangular meshing subdivision surface model;(2) An algorithm for k nearest neighbors querying through the area growth of dynamic and hollow sphere based on R*S-tree was proposed, which solved the problem querying the topological neighbors of the triangular dough sheet on the triangular meshing subdivision surface model effectively.(3) Triangular meshing subdivision surface model was organized base on the space clustering index construction R*S-tree. The triangular dough sheet intersecting with the cutter section were obtained quickly through depth-first traversing R*S-tree according to the position between the cutter section and the MBR of the index node of R*S-tree. The points of NC tool path were generated according to the geometric properties on differential calculus of surface position corresponding to tool touching points following the cutter location points were ordered by using the minimum spanning tree algorithm and the NC processing for triangular meshing subdivision surface model was realized.(4) The blank model was established by use of triangular discrete mesh. The sweepage surfaces formed of milling by three kinds of mill tool were researched. The lowest position of various nodes was obtained through computing the intersection between the discrete mesh nodes of blank model and the sweepage surface of mill tool. The emulation was realized through refreshing the lowest position of various nodes by use of VTK which is a visual tool to inspect the correctness of generated tool path.