How do you know that the machine tool has been setup correctly?
Well the Heidenhain 640 has an option to calculate the exact kinematics this is especially useful if the 5th axis unit is removable from the machine tool or when the machine ages.
The Heidenhain software does not just work right from the start, the physical Kinematics have to be calculated and entered into a Kinematics table. Once these have been found the clever controller finds the exact errors in the Tilting / Turning axes.