A cylindrical profile measurement method for cylindricity and coaxiality of stepped shaft

Abstract

The cylindricity and coaxiality of the stepped shaft are important parameters reflecting the vibration characteristics of the rotating machines system. In order to evaluate the cylindricity and coaxiality of the stepped shaft accurately, the paper proposes a cylindrical profile measurement model, which takes into account five kinds of systematic errors and analyzes the combined effects of five systematic errors on cylindrical profile measurement results. Based on the proposed measurement model, the distribution of sample angle deviation caused by five systematic errors is studied. A non-uniform spline filter is designed, and the effect of uniform and non-uniform spline filter methods on the cylindricity and coaxiality of stepped shaft are analyzed. In order to verify the effectiveness of the cylindrical profile measurement model with five systematic errors and the spline filter method proposed in the paper, a rotary measuring instrument with high precision is built. The experimental results show that compared with the traditional measurement method, the measurement accuracy of cylindricity and coaxiality can be improved by 11.43 μm and 8.99 μm for stepped shaft with large radius on the proposed method, respectively. The proposed method is suitable for small probe radius and large eccentricity error, probe offset error, workpiece tilt error, and guide rail tilt error, especially for stepped shaft with large radius, such as aerospace engine, gas turbine, and machine tools.