Evaluation of a Coordinate Measuring Machine by Using a Three-dimensional Tracking Laser Interferometer.

A new method for evaluating the coordinate error of commercial CMMs by using a newly developed three-dimensional tracking laser interferometer is proposed. The length between a moving Cats'-eye retroreflector set to the probing head of a CMM and the rotation center of the 3 D tracking interferometer is measured and used for estithating the coordinate error at each sampled point based on nonlinear least squares. The measurement accuracy with the proposed method including the optical path accuracy of the Cats'-eye retroreflector and the structural accuracy of the tracking mechanism is evaluated both theoretically and experimentally.