A Method for Measuring Mutual Reference Parallelism Based on Correspondence Measurement

With the development of high-end equipment manufacturing industry, the demand for parallelism measurement of precision components is increasing day by day. Taking aircraft engine bearings as an example, due to the lack of specified benchmarks for their inner and outer ring end faces, high-precision parallelism evaluation needs to be conducted based on mutual benchmarks. However, the traditional single reference measurement mode not only fails to ensure the accuracy of correspondence detection of biplane contours, but also causes distortion of measurement results due to the shape error of the reference surface itself. To address this issue, this article proposes a parallelism measurement method based on synchronous scanning of dual displacement sensors: by constructing a composite motion mechanism containing orthogonal linear motion axes and rotation axes, the full surface scanning of the measured object is achieved; Using geometric constraints with fixed spacing between dual sensors to ensure strict correspondence between spatial coordinates of dual plane measurement data. By combining the least squares plane fitting algorithm, the accurate calculation of the biplane angle is achieved, and the precise evaluation of parallelism is ultimately completed. The experimental results show that the method achieves a repeatability standard deviation of 0.38″ (approximately 1.84 μ rad), providing a reliable technical solution for parallelism measurement of unspecified reference structures such as aviation bearings.