Abstract
Ball plates have been increasingly used for checking the performance of coordinate measuring machines (CMMs) in Japan. In future, the ball plate will become a popular gauge for checking or calibrating the CMM in Japan. Therefore, we organized two ball plate round-robin measurements to create the opportunity to relay our calibration technique to other institutes. On the first round-robin, sixteen institutes including NMIJ participated and the measurements took place from October 2003 to September 2004. On the second round-robin, six institutes including NMIJ participated and the measurements took place form November 2004 to May 2005. We describe the results of the two comparisons in this paper.
