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The Estimation of Measurement Uncertainty of Small Circular Features Measured by CMMs



Steven D. Phillips, Bruce R. Borchardt, William T. Estler


This paper examines the measurement uncertainty of small circular features as a function of the sampling strategy, i.e., the number and distribution of measurement points. Specifically, we examine measuring a circular feature using a three-point sampling strategy in which the angular distance between the points varies from widely spaces, 120 degrees, to closely grouped, a few degrees. Both theoretical and experimental results show that the measurement uncertainty is a strong function of the sampling strategy. The uncertainty is shown to vary by four orders of magnitude as a function of the angular distribution of the measurement points. A conceptual framework for theoretically estimating the measuring uncertainty is described and a good agreement with experiment is obtained when the measurements are consistent with the assumptions of the theoretical model.
NIST Interagency/Internal Report (NISTIR) - 5698
Report Number


Phillips, S. , Borchardt, B. and Estler, W. (1995), The Estimation of Measurement Uncertainty of Small Circular Features Measured by CMMs, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD (Accessed April 18, 2024)
Created February 1, 1995, Updated February 19, 2017