Abstract:

In order to avoid the low average feedrate, discontinuous machining path and strong vibration shock in the machining process of consecutive micro line blocks, a real-time smoothing interpolation method based on NURBS curve fitting is proposed. In this method, by analyzing the geometric characteristics and machining tech- nique of the consecutive lines, a length ratio criterion and a critical angle criterion of adjacent lines are presented to pick out the appropriate point sequence. The point sequence is divided into many subsections based on the concave and convex criterion and is then fitted to obtain parametric curves. Finally, by combining the linear interpolation and the parametric curve interpolation, a high-speed smoothing machining is successfully implemented. Simulated and experimental results demonstrate that the proposed method effectively improves the machining speed, reduces the machining vibration and ensures the machining accuracy.

Key words: NURBS, curve fitting, micro line block , high-speed machining, interpolation