Abstract
This paper describes a three-dimensional coordinate comparator using a reference workpiece with the same material and geometrical profile as the measuring workpieces. Because of little influence of the temperature change, this measuring machine can be utilized in shop-floor thermal environment instead of a conventional coordinate measuring machine which measures absolute coordinate values. Moreover, the comparator's geometrical deviation and the probe's error have little effect on the measured values. Measurement results using gauge blocks, and optical flat and workpieces with complicated profile show that this comparator has measurement uncertainty less than ±1 μm regardless of temperature change of several degrees.
