Straightness and index sensor with sub-micron accuracy

Straightness measurements are important for machine axes correction or qualification. In this paper we investigate the accuracy of an optical straightness measurement system based on a fibre coupled laser beam pointing onto an image sensor. With sub-micron accuracy, such a simple and economic system is an interesting alternative to standard calibration techniques and can even be implemented on machines for real time correction. This paper investigates the achievable accuracy for measuring ranges up to 1.5m.