An Analytical Corner Rounding Algorithm With G01 Shape Preserving for Five-Axis Computer Numerical Controlled Machining

Abstract

G01 blocks are the widespread format of toolpath in computer numerical controlled (CNC) machining. For achieving smooth motion and eliminating the geometrical discontinuity at the block transitions, various local corner smoothing methods have been developed. However, in these methods, the loss of featured information of parts is inevitable. Focused on this topic, this article proposes a new analytical G2 continuous corner smoothing method with G01 shape preserving for five-axis linear toolpath by locally inserting specially designed B-splines into the corners of consecutive segments. First, by analyzing the condition of G01 shape preserving, the configuration expression of control points for B-splines is yielded for passing through G01 point. On this basis, the tool tip position is smoothed by symmetrical B-splines with minimum curvature in the workpiece coordinate system (WCS). Then, another asymmetrical B-splines is used to smooth tool orientation in the machine coordinate system (MCS). After that, the satisfaction conditions of parametric synchronization between tool tip position and tool orientation are mathematically derived at junctions, while the corresponding maximum smoothing errors are also constrained in WCS. Compared with the existing methods, not only the tool tip points and orientation vectors specified in original G01 blocks are preserved but also the optimal control points considering the curvature of smooth splines can be obtained analytically. Finally, simulations and experiments are performed to validate the effectiveness of the developed method.