A laser interferometer-based system for automatic calibration of height setting micrometers is reported. The system consists of a vertical air slide, a two-frequency laser interferometer, a linear-motor driven horizontal slide and an electronic probe, all interfaced to a PC. A software written in C language has been developed to control the system and carry out the calibration. The performance of different types of probes is compared. Details of the system design, its own calibration, uncertainty budget and system performance are described. The new system has a measuring range of 350mm, resolution 40nm, expanded uncertainty of height measurement better than 0.5μm at 95% confidence level over full range. The whole calibration procedure can be completed within an hour. It is much more efficient and accurate than the conventional method - direct comparison with standard gauge blocks.
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