Variable speed compensation method of errors of probes for CNC machine tools

Systematic errors of kinematic touch-trigger probes for CNC machine tools may exceed errors of the machine tool itself. As a result, the machining accuracy is strongly dependent on the probe's accuracy. Numerical correction of probes' systematic errors can be used. However, it requires executing calculations by the CNC machine tool controller. To avoid this troublesome requirement, a new method of errors compensation is proposed. In this approach, a modification of the probe's pre-travel in a given direction is achieved by modification of measurement speed in this direction. Because all measurement speeds can be calculated offline, the controller does not have to do any calculations. The proposed method has been tested for sample kinematic probes and the error reduction was at least 10-fold.