Gao Ge received her B.S. degree from Northwestern Polytechnical University (NWPU) in 2010, and now is a postgraduate. Her main research interest is machining technology.E-mail addresses: gaogeflying@163.com (G. Gao) Zhang Dinghua received his B.S. and M.S. degrees from Northwestern Polytechnical University in 1981 and 1984, respectively. He also received his Ph.D. degree in Aeronautical and Astronautical Manufacturing Engineering from Northwestern Polytechnical University in 1989 and became a professor there in 1991. His main research areas of interest include multi-axis machining, high-speed machining, machining surface integrity, and industrial CT technology. Corresponding author. Tel.: + 86 29 88493009. E-mail addresses: dhzhang@nwpu. edu.cn (D. Zhang).