The studies of spline interpolation for five-axis machining

The study proposed a dual uniform B-spline interpolator architecture for computer numerical control (CNC) machines spline machining. For solving the different transformation in machining sculpture surface with five-axis machine tool, the format of G codes for five-axis spline interpolation is presented. Quaternion B-spline curves are adopted to describe the movement of rotary axis of five-axis machine, relative to conventional five-axis linear interpolation and other kinds of spline, using quaternion B-spline can accurately describe the rotation movement, all the interpolation results locate at the unit sphere surface, which makes the rotation movement more precise and reliable, and promoting the machining quality. This paper also presents the method for converting off-line interpolation of discrete cutting path into dual B-spline and interpolator algorithm of five-axis spline. Simulation curves are plotted to analyze the performance of spline interpolator, and the simulation results show that the feedrate is smooth. In the end, one impeller part's slotting machining process step is provided to verify the performance of spline interpolator, and the spline machining result compared with the five-axis linear interpolation result. The experiment results show that the spline interpolator can notably promote the machining surface quality.