Abstract: A new algorithm for numerical control tool path generation of the triangular Bézier surface models is proposed, which can be used to improve efficiency of the finishing tool path generation and solve the interference issues of tool path. The topological structure of the triangular Bézier patches is organized by the dynamic index and the intersecting regions are quickly obtained based on the dynamic index; the whole cross border intersection curve is traced by starting from initial intersection point; the cutter local points are obtained through the offset of points on intersection curve; the interference region is positioned according to the relationship between surface normal vector of cutter contact point and tool axis vector, and then the cutter location points within the interference region are adjusted, so that the cutter location points are interference-free; the cutter location points are connected rightly to generate tool path. The experimental results show that this method has strong adaptability and can get numerical control tool path rapidly and it is proved that it is applicable through generating NC tool path for triangular Bézier surface based on this algorithm.

Key words: Dynamic index, Surface intersection, Tool path generation, Triangular Bézier surface