R-test, a new device for accuracy measurements on five axis machine tools

When rotary axes (rotary tables and/or swivelling axes) are used in combination with linear axes, the position and the orientation of the rotary axes have to be known accurately, because these parameters strongly influence the accuracy of the machined work piece. The new device measures X, Y, Z deviations of circular and spherical movements simultaneously on continuous paths. These deviations are used to calibrate parameter errors like backlash, positioning error, squareness, parallelism, etc. The uncertainty budget of the measurements is presented and effects of thermal influences are shown. Measurement results on a serial five-axis machine and on the parallel kinematic machine tool Hexaglide are shown and discussed in detail.