A new toolpath generation method with feed sensitive zones inspection based on inverse evaluation mechanism

Abstract

Toolpath generation is the crucial task of free-form surface machining, and the quality of toolpath affects the final machining precision and efficiency. In conventional method, machining efficiency is approximately evaluated by the length of toolpaths. However, due to the curvature of toolpath distributing irregularly, the axis drive has to accelerate or decelerate to avoid exceeding its limits. For this reason, interpolation situation would affect toolpath quality as well, which is not taken into consideration in the traditional toolpaths generation mechanism. This paper proposes a toolpath generation method to plan toolpath with time-optimal, which has bidirectional information flow between CAM system and CNC system. This architecture is called inverse evaluation mechanism. By this mechanism, an offline simulation interpolation module is integrated into the CNC system; with this module, the feed sensitive zones are inspected by CNC system and the surface is divided into normal zones and low-velocity zones. The low-velocity zones are transmitted to CAM system as the feedback information. This paper gives the whole architecture of inverse evaluation mechanism and the details of how it works. The proposed method is verified with simulation examples; the result shows that this method can automatically find the low-velocity zones and modify the toolpaths.