Smooth trajectory generation for five-axis machine tools

• Five axis machining accuracy is improved by smoothing the tool paths and axis commands.
• Original, five axis tool path is fitted to a quintic spline with geometric jerk continuity.
• Feed correction splines are fitted to the tool tip positions orientations.
• Splined axis commands reduce frequency content and inertial vibrations of the machine.
• Smoothed axis commands are shown to reduce tracking errors experimentally.

This paper presents a smooth spline interpolation technique for five-axis machining of sculptured surfaces. The tool tip and orientation locations generated by the CAM system are first fitted to quintic splines independently to achieve geometric jerk continuity while decoupling the relative changes in position and orientation of the cutter along the curved path. The non-linear relationship between spline parameters and displacements along the path is approximated with ninth order and seventh order feed correction splines for position and orientation, respectively. The high order feed correction splines allow minimum deviation from the reference axis commands while preserving continuous jerk on three translational and two rotary drives. The proposed method has been experimentally demonstrated to show improvements in reducing the excitation of inertial vibrations while improving tracking accuracy in five-axis machining of curved paths found in dies, molds and aerospace parts.