An efficient on-site calibration method and precise measurement model for miniaturized rotational parts based on four-axis linkage spatial measurement system

Abstract

The key geometric parameters of miniaturized rotational parts significantly influence the overall performance and service life of equipment, such as bore diameter, roundness, cylindricity, generatrix contour, etc. However, most existing measurement technologies are aimed at certain types of parameters and fail to provide full-scale and high-precision measurements, especially when measuring space is limited. In this paper, a 4-axis linkage spatial measurement system is established, equipped with a precision air-floating turntable and a compact fiber optic probe. Innovations include: (1) An efficient 4-axis linkage calibration method is proposed. This method can achieve precise calibration of the laser direction vector or the rotation axis position with only a single scan; (2) On this basis, a polar-coordinate measurement model for any positive section of rotational parts is proposed, eliminating the negative impact of part offset on measurement accuracy. Experimental results show that the measurement error of the diameter, the roundness and the cylindricity is approximately $3\mu m$, $2\mu m$ and $2.8\mu m$, respectively. The average measurement error of the generatrix contour is $4\mu m$. Compared with the traditional contact coordinate measuring machine, the overall measurement efficiency is improved by about 67%, demonstrating that this method meets the requirements for on-site efficient and precise measurement of miniaturized rotational parts.