Calibration system for tactile measuring probes

Information about procedures and equipment for the calibration of linear displacement probes are rare in the literature. The paper first discusses the key properties of published systems with nanometer resolution followed by the description of a new calibration system having 50 nanometer measuring uncertainty. The probe displacement is generated by a single-axis positioning stage driven by a stepping motor. The tip of the probe touches the backface of the flat mirror with flatness better than λ/100, attached to the stage, acting as the retroreflector of the plane mirror laser interferometer. Angular sensors are used to capture the angular deviation of the mirror at the measuring positions. The probe error is the difference between the output of the probe and the value measured by the laser interferometer. Finally the calibration uncertainty and measurement results discussed to show the systems performance.