Identification of geometric deviations of a motion guide in a coordinate-measuring machine or in a machine tool

A method for identifying geometric deviations of a real motion guide from an ideal motion guide in a coordinate-measuring machine having a sensor for measuring a workpiece, or in a machine tool having a tool for processing a workpiece, wherein the coordinate-measuring machine or the machine tool has a movable part which is guided along the motion guide and by the motion guide, including the steps of:

• moving the movable part in a forward direction along the motion guide, and recording in each case one measurement value of the geometric deviation at a plurality of first positions of the movable part with respect to the motion guide, with the result that a first group of measurement values is recorded,
• moving the movable part in a backward direction, which runs counter to the forward direction, along the motion guide, and recording in each case one measurement value of the geometric deviation at a plurality of second positions of the movable part with respect to the motion guide, with the result that a second group of measurement values is recorded,
• wherein during the recording of the first group of measurement values, no measurement value is recorded at at least one first intermediate position which is situated between two of the first positions at one of the second positions, and/or wherein during the recording of the second group of measurement values, no measurement value is recorded at at least one second intermediate position which is situated between two of the second positions at one of the first positions, and
• for each of the first positions and for each of the second positions, calculating an average of the geometric deviation of the motion guide from the profile of the first group of measurement values along the motion guide and from the profile of the second group of measurement values along the motion guide, and forming a group of averages which are the averages of the geometric deviations when moving the movable part in the forward direction and in the backward direction.