Smooth fillet-end cutter tool path generation method on triangular-mesh surface based on Modified Butterfly subdivision

Abstract

Triangular-mesh surfaces are widely applied in the design of aerospace, automobiles, ships, etc., because of their high computational efficiency and robustness compared with parametric surfaces. In order to improve the tool path continuity and reduce the cutter load fluctuation, a smooth tool path generation method on triangular-mesh surfaces based on Modified Butterfly subdivision is proposed. The machining model at the cutter-contact point is constructed based on the geometric analysis of the triangular-mesh surface and fillet-end cutter. The minimum cutter tilt angle and maximum machining stripe width are obtained to avoid the interference of cutter and workpiece. And then, the Modified Butterfly subdivision method is applied to the triangular-mesh surface to ensure the tool path interval within the strip width. The boundary of the surface is selected as the initial tool path based on which the subsequent tool paths are generated along the edge of triangular mesh, and the cutter location points are obtained according to the geometric model of the fillet-end cutter. The Discrete Domain of Feasible Orientation (DDFO) model is constructed to eliminate the singularity problem of the machining process, and Modified Butterfly subdivision is applied recurrently to guarantee the whole surface within the scallop height requirement. Finally, the spiral tool path with good continuity and smoothness is generated according to the specified cutter parameter and scallop height requirement, which can reduce the cutter load fluctuation.