Five-axis toolpath interpolation method with kinematic corner smoothing and time synchronization

Abstract

osMost toolpaths of high speed five-axis machining are composed of discrete tool positions and tool orientation vectors. Thus, toolpath smoothing is essential for increasing the machining efficiency and quality. Traditional smoothing methods face the difficulties of synchronization, computational load, feedrate fluctuation and overshoot due to the inefficient procedure of geometric smoothing followed by interpolation. To break these bottlenecks, a novel interpolation method for five-axis toolpaths with kinematic corner smoothing and time synchronization is proposed in this paper. Rather than smoothing the toolpaths geometrically, the translational velocity of tool position and the rotary angular velocity of tool orientation are directly scheduled in the workpiece coordinate system (WCS). Additionally, algorithms of time synchronization and interpolation are proposed to synchronize translation with rotation, and calculate interpolated tool positions and orientations efficiently. Simulation and experimental studies are conducted to validate the effectiveness and feasibility of the proposed method. Compared with a geometric corner smoothing method, the proposed method generates interpolated toolpaths perfectly respecting the geometric and kinematic constraints. Both the tangential and the axial kinematic profiles obtained by the proposed method are smooth and free of jitters at block junctions. Furthermore, the proposed method improves the machined surface quality, and reduces the computational time by over 50 % without solving optimization problems or scheduling recursively.