Efficient Calibration of a Scanning Probe on CMM.

Scanning probes would achieve superior accuracy and efficiency compared to touch-trigger probes when performing measurement on a Coordinate Measuring Machine(CMM). However, existing research has found that the calibration time for scanning probes is much longer than that for touch-trigger probes, owing to the complex calibration setups and procedures of current methods. For industrial inspection applications requiring multiple probe angles, calibration time significantly impacts on overall efficiency. In this paper, we design a scanning probe based on three-layer parallel leaf-springs and three orthogonally arranged displacement sensors. A semi-linear mathematical model with a minimal number of parameters is established for this probe. By fully utilizing all data collected during the probing, the proposed method simplifies the calibration procedure, requiring only 25 points to be probed on a sphere artifact. Four sets of precision tests are conducted to compare the accuracy of the proposed calibration method with Renishaw’s commercial calibration method on the designed probe and Renishaw’s SP25 probe is used as the benchmark. The results demonstrate that our calibration method can achieve similar or even higher accuracy compared to Renishaw’s calibration method. Moreover, our calibration time is only 36.6% of that of Renishaw’s method, which validates our proposed method. This advancement holds promising implications for enhancing productivity in industrial CMM applications.