A circumscribed local interpolation methodology for CNC machining along linear tool paths

ABSTRACT

The G01 tool path, which consisted of linear segments, is commonly used in NC machining. There is the tangential and curvature discontinuity at the junctions of adjacent linear segments, which can cause the fluctuations of feedrate and deteriorate surface quality. In this paper, a novel circumscribed local interpolation method is proposed to smooth the discrete path and consequently improve the kinematic performance of the machine tool. The polygons are firstly constructed with a constraint of the maximum approximation error. Then, the double cubic Bezier curves are used to smooth the corner between two linear segments and the control points are derived according to the G2 continuity condition and the length constraint. Further, the motion profile along the blended tool path is generated by utilizing the quantic polynomial feedrate scheduling strategy. Finally, the proposed smoothing method is validated by simulations and experiments.

KEYWORDS:

• Interpolation
• Bezier curves
• NC machining
• G² continuity

Acknowledgments

This work was supported by the NSFC (Grant No. 91948203) and NKRDPC (Grant No. 2018YFA0704603).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [91948203]; Ministry of Science and Technology of the people’s Republic of China NKRDPC [2018YFA0704603].

Notes on contributors

Fuyang Xu

Fuyang Xu is a master student of school of mechanical engineering at Dalian University of Technology, China. He received the B.S. degree (2015) in mechanical engineering at Dalian University of Technology. His research interests include toolpath planning and federate scheduling for five axis machining.

Mansen Chen

Mansen Chen received the B.S. degree in mechanical engineering from North University of China, Taiyuan, China, in 2014. He is currently working toward the Ph.D. degree in mechanical engineering from the School of Mechanical Engineering, Dalian University of Technology, Dalian, China. His research interests include computer numerical control systems, intelligent manufacturing and precision machining technology.

Yuwen Sun

Yuwen Sun is a professor of school of mechanical engineering at Dalian University of Technology, China. He received the B.S. degree (1994) in mechanical engineering at Xi’an Jiaotong University, and the Ph.D. degree (2000) in mechanical engineering at Dalian University of Technology, China. His research interests include modeling, simulation and optimization for manufacturing process, digital manufacturing and CNC Machining technology, reverse engineering, precision & non-traditional machining technology.