Axis location and scale factors estimation for three-axis machines from periodic performance checks with laser distance measurements - risks and opportunities

Users of coordinate measuring machine and large gantry machines need to ensure the volumetric performance of their machines in order to inspect, or machine, mechanical parts with precision. In the case of CMMs, the ASME B89.4.10360.2-2008 document imposes seven directions for a volumetric check. These directions offer some redundancy for axis location (out-of-squarenesses) and scale factor estimation. The paper looks at the opportunity of using the data for immediate machine correction and the risks involved. In particular, the fact of using test data for calibration and verification, the potential contamination from non-modelled motion errors and the representativity of the estimated parameters are considered. Experimental results obtained using laser interferometry on a LEGEX CMMs are used to present the main concepts