Machining, Measurement, and Control Laboratory

The Estimation of Three-dimensional Volumetric Errors by Laser Step Diagonal Measurement
Takafumi Hata, Soichi Ibaraki, Atsushi Matsubara

The laser step diagonal measurement is a method for the identification of all the volumetric error components, including linear displacement errors, straightness and squareness errors by using only a laser interferometer and a flat mirror. This research first discusses inherent and critical issues with the conventional formulation of the laser step diagonal measurement. Then, we propose a new formulation of the laser step diagonal measurement to accurately estimate the machine’s volumetric errors even under the existence of setup errors. As a case study, the proposed formulation is applied to estimate volumetric errors on the three-axis commercial machine tool. Experimental results show that straightness and squareness errors can be identified with the estimation error of about 1um over the measurement distance of 120mm.