Straightness Measurement Of Long Guide Rail Based On Opitical Scanning Method

Straightness is the main geometrical errors for guide rail. For motion platform rail,straightness errors directly affect the accuracy of machine tools, measuring machine. Withthe progress of ultra-precision machining technology, the requirements of guide railstraightness measurement are also increasing. The traditional method such as ruler, lineweight measurements and other simple tools are easy for measurement, but themeasurement accuracy and performance is not guaranteed. The modern measuringmethods-laser collimator’s advantage is high precision and high speed, but its condition ofapplication is limited, and the online measurement of the installed guide rail isdiscommodious.In this paper, A new optical scanning method, which uses three-probe displacementsensors with tilt compensation is proposed for the on-line straightness measurement of thelong guide rail. It can be implemented on a non-contact guide rails and continuous fastscanning measurement, reconstructed accurately express the high frequency element ofstraightness error. It also owns better suppression capability of the measurement noise.First, the existing rail straightness scanning measurement methods are introduced. Second,the measurement principle and the computer simulation results for three-probe methodwith tilt compensation are descripted in detail. At last, we build the experimental systemfor verificating the proposal method. We wrote the corresponding data collection programand straightness reconstruction program. The experimental results of the guide railstraightness measurement showed that the proposed method can accurately reconstruct thestep form，the measurement accuracy is less than10microns.