Optimal control method for the sphericity error using CMMs

Spherical surfaces are utilized widely in precision bearing, MEMS and parts of precision engineering. Constantly growing needs in the high motion performance of spherical parts, sphericity error is becoming an indispensable component in the control of form error. However, currently the quality control of a spherical surface is restricted by the lack of science-based mathematical models. This paper presents a unified approach to evaluate sphericity error using three methods: Least Square Sphere, Minimum Zone Sphere, Maximum Inscribed Sphere. The research originated from the need compare the effectiveness of these methods for different requirements for measurement accuracy. Three experiments are used to verify the effectiveness of the methods with 28, 36 and 50 datasets measured on Coordinate Measuring Machines. Presents a mathematical models of sphericity measurement and comparative results of the verification of these models.