Abstract: To realize the reversal design and manufacture of product based on the triangular Bézier surface modeling technology, a generating algorithm of contour-parallel tool-path for triangular Bézier surface model was proposed. Through optimizing R*-tree's construction process, dynamic index of triangular Bézier surface model was established. The triangular Bézier surface patches in instant processing region were acquired based on proposed index, and interference-free cutter location points were iteratively calculated by using tool surface discription method. Z-direction envelop of triangular Bézier surface was built, and topological neighbor relations of Z-direction envelop were organized based on R* tree. The contour loops were obtained by intersection of Z-direction envelop and cutting plane, and the cutting area was determined. Thus contour-parallel rough tool-path was obtained. Through examples, the algorithm was proved to generate interference-free cutter contour-parallel rough tool-path for complex triangular Bézier surface.

Key words: triangular Bézier surface, R*-tree, Z-direction envelop, contour-parallel rough tool-path, interference-free cutter location points

摘要： 为实现基于三角Bézier曲面造型技术的产品逆向设计与制造，提出一种针对三角Bézier曲面模型的平头刀环切粗加工刀轨生成算法，该算法通过优化R*树的构建过程，建立了三角Bézier曲面模型的动态索引，基于该索引快速获取瞬时加工区域三角Bézier曲面片，进而采用刀具表面离散的方法迭代计算无干涉刀位点，并建立了三角Bézier曲面的Z向包络面，采用R*树组织Z向包络面的拓扑近邻关系。将切削平面与Z向包络面求交获取截面轮廓环，并由它们之间的包含关系确定切削区域，进而获取环切粗加工刀轨。通过实例证明了该算法可对复杂三角Bézier曲面生成平刀无干涉环切粗加工刀轨。

关键词: 三角Bézier曲面, R*树, Z向包络面, 环切粗加工刀轨