A new design concept for milling tools of spherical surfaces obtained by kinematic generation

In this paper, the authors show an original methodology for optimization of tool geometry used in the milling of spherical surfaces. This methodology is based on thorough theoretical research, which highlights the kinematic characteristics of spherical surface generation by milling. These characteristics lead to the conclusion that the constructive angles of tools used in spherical surface milling must have the same values on both cutting edges.The paper also presents a practical design methodology of these tools, both for exterior spherical milling, and for interior spherical milling.The theoretical research was validated by manufacturing physical tools used in processing spherical joints from 330 MW turbines, as well as in processing of sphere taps used in the petrochemical industry.