Interim check and compensation of geometric errors to improve volumetric error of machine tools

In the manufacture of mechanical components, volumetric errors of a machine tool should be checked and reduced to meet the required tolerance levels. In this paper, we propose a quick and simple method of measurement for checking and compensating geometric errors which include scaling and squareness errors. During the measurement, which usually takes approximately 5 minutes to complete, the machine tool is first commanded into four vertices sequentially on a virtual regular tetrahedron. Subsequently, the six lengths between four vertices are measured using a double ball-bar and geometric errors are calculated from the measured lengths. In order to verify the measurement result, the measured geometric errors are compensated using NC-code and the six lengths are re-measured to confirm the error correction. In conclusion, a double ball-bar circular test on XY-, YZ-, ZX-plane is done, first without compensation and then with the compensation of the measured geometric errors to check the effect of compensation practically.