PROFILE MEASUREMENT WITHOUT REFERENCE ERROR COMPARING TWO PARALLEL LINEAR STAGES

In general, the profile measuring machine uses the displacement sensor attached on movable mechanism in order to measure the object. It could measure the object profile by the amount of movement of the displacement sensor and output of the displacement sensor. When measuring the object, metrological frame is important as a reference. If the metrological frame has some profile errors, the output of the displacement sensor includes the profile error of the metrological frame. We proposed a new method to distinguish the profile error of the metrological frame from the output of the displacement sensor. The proposed method requires two linear stages and the displacement sensor. Two linear stages are set and aligned in parallel; displacement sensor and object are mounted on each stage. The output of the displacement sensor can be obtained by the combination of the position of the two linear stages. The object profile and profile error of the movable mechanism are determined by calculation using only the output of the displacement sensor. The validity of the new method was confirmed by the simulation and experiment. It was confirmed to be possible to construct metrological frame less than 1 µm.