Measurement and optimization of coaxiality in the assembly of aero-engine rotor by decoupling evaluation datum and component datum

Coaxiality optimization ensures the assembly quality of aero-engine rotor through assembly planning to reduce vibration during operation. Coupling of coaxiality evaluation datum and component datum results in a minimum coaxiality error constraint and a fixed error transmission path during measurement process, limiting the optimization effectiveness. This paper proposes a coaxiality optimization method that decouples the evaluation datum and the component datum. This method consistently uses the rotary axis of the air bearing table as the coaxiality evaluation datum. An optimal combination approach of the evaluation datum and the component datum is determined by performing a two-dimensional optimization on the component datum and its orientation. Subsequently, the assembly angles of each level of components are iteratively adjusted to achieve coaxiality optimization. An analysis of the influence of datum combination approach for three levels of components is presented, along with an assembly experiment on the aero-engine rotor. The results show that, compared to the datum coupling method, the proposed approach eliminates the constraints imposed by component datum eccentricity on coaxiality optimization and achieves better optimization results. This method offers an optimal coaxiality assembly plan for aero-engine rotor and can also serve as a foundational model for intelligent optimization methods.