Machine Vision Systems (MVS) are increasingly used in manufacturing metrology for point coordinates acquisition, parts geometry verification, defect detection, etc. as high-resolution, low-cost image and dense data-acquisition sensors and lens systems become broadly available. To explore MVS’s application on machine tool calibration, we propose a prototype of an R-test type stereo camera measuring devices mounted at the spindle for machine tool volumetric error measurement. The prototype has a stereo-camera pair to track a 3D spherical target center positions relative to one of the camera reference frame. The calculated sphere center positions were obtained for 125 nominal positions uniformly distributed grid inside a 0.8 × 0.8 × 0.8 mm 3 cubic volume generated by a machine tool’s G-code commands. The error vectors are calculated as the differences between the calculated and nominal sphere centers, and the point distance errors are calculated as the norm of the error vectors. The results show that 120 points have error norms less than 0.015 mm. The proposed device shows good potential to measure volumetric errors for five-axis machine tool calibration as an R-test non-contact device. Future work should improve the quality of the image, the accuracy of sphere center calculation and the stiffness of the packaging.
Zhuang et al. (Thu,) studied this question.