Principle and Method for Machining Face Gear with Developable Ruled Surface Xianlong Peng, Yanyan Hou, Le Zhang, Feiyan Han and Farong Kou JNWPU, 38 6 (2020) 1299-1307 Published online: 02 February 2021 DOI: 10.1051/jnwpu/20203861299