Cutter orientation planning in NC machining for surface similar to revolution body with considering kinematic characteristics

Abstract

In multi-axis numerical control (NC) machining of curved surface with high feed rate, vibration and shock will occur when the velocity and acceleration of the machine tool axis exceed the limit value, which will influence quality of the part surface. Aiming at the NC machining of surface similar to revolution body with high feed speed, a method of cutter orientation planning meeting kinematical constraints that the velocity and acceleration of the machine tool axis cannot over the maximum value is proposed in this paper. First of all, considering the velocity characteristic constraint, the relationship between cutter orientation and the velocity of motional axis is analyzed in machine tool coordinate planes. According to the distribution of the polar radius difference of adjacent cutter location points, the angles between each adjacent cutter orientations are obtained, and these angles are adjusted by an allowable minimum angle. All preliminary cutter orientations are determined by defining the cutter orientation at the first cutter location point. Then, analyzing the acceleration characteristic of motional axis, the acceleration mathematical optimization model is established. Final cutter orientation is determined, and the feed rate machine tool is adjusted by optimization method. Finally, taking shoe last surface as processing example and obtaining cutter orientations by using the proposed and existing methods, respectively, the effectiveness of the method presented in this paper is approved.