精密角度検出器を用いた真直度測定方法の精度解析

概要

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Accuracy of the straightness measurement is analysed applying additive theorem of variance, and the following formula of 95% confidence limit is derived ; e(n, r, 0.95)=t(φ_E, 0.05)1/√r・√<<n+1>/2>(1σ_θ) where n; number of measuring steps, r; number of replication of measurements, t(φ_E, 0.05); 5% point of t-distribution of φ_E=(n-1)(r-1) in degree of freedom, l; length of a step of measurement, σ_θ; standard deviation of angle measurement of an autocollimator. The formula is applied to the measurement of guide ways of machine tools such as 12 m KWB Roll Grinder and Ultra High Precision Machine Tool manufactured by Toshiba Machine Co. Ltd. by an autocollimator of 0.5 s in scale interval, and the following results are obtained : (1) Factorial experiment with replication is effective at the measurement, for standard deviation lue can be obtained as square root of unbiased variance of error in the ANOVA. (2) Standard deviation 1σ_θ depends not only on fluctuation of angle measurement and the step length but also on surface finish of the guide way, atmospheric fluctuation of room temperature, rigidity of con-struction and others. (3) 1σ_θ is 0.26 μm at planed bed of the roll grinder measured under temperature condition of 26^+_-1℃, and 0.13 μm at lapped guide way of the Ultra High Precision Machine Tool under 20^+_-0.2℃.
公益社団法人精密工学会の論文
1984-08-05