Measurement Setup and Procedure for Precise Step Gauge Calibration

Abstract

The rapid increase in precision of tactile coordinate measurement machines (CMMs) in recent years has caused an increased demand for high precision calibration artifacts, by which the traceability of coordinate measurements can be assured. This article presents research done in the development and verification of a high precision calibration system for step gauges, which are among the most frequently used CMM calibration artifacts. The main goals for the calibration system are measurement uncertainty of ${U}= ({{{(0.1}\,\,{{\mu m)}}}^{{2}}+{{(0.5\cdot }{{10}}^{{-6}} {\cdot L)}}^{{2}}})^{1/2} $ and full automatization of the measurement process, with human intervention only needed during the initial setup of the step gauge onto the system. Final verification has confirmed that both goals were achieved. The automation allows for autonomous measurement of the step gauge after the operator has performed the step gauge setup and entered nominal values of the measurement points, as well as the number of repetitions.