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Xue Zi
Tan Jiubin
Zhao Weiqian
Institute of Ultra Precision Optoelectronic
Instrument Engineering,
Harbin Institute of Technology,
Harbin 150001, China
Zhang Heng
Length Division,
National Institute of Metrology,
Beijing 100013, China |
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ALTERABLE
INTERVAL
OPTICAL-
ELECTRONIC
AUTOCOLLIMATION
METHOD FOR
STRAIGHTNESS
MEASUREMENT OF
PRECISION
GUIDE*
Abstract:
Optical-electronic autocollimation method is commonly used to measure straightness of precision guides in engineering application. However, the traditional fixed interval optical-electronic autocollimation method is not suitable for measuring straightness of an air-bearing guide with a long air-bearing bush or a precision straight guide with a long slide-carriage, because the air-bearing bush and the slide-carriage are actually taken as a big bridgeboard bigger than the length of the bridge-board with the reflector, which is about 1/4~1/2 of total length of the measured guide. If straightness is measured according to the traditional method, only a few points are sampled so that the guide straightness can not be evaluated fully or accurately. In order to solve the problem, an alterable measuring interval method is proposed for straightness measurement based on analyzing the mutual relations and effects among the tilting angle of the reflector, the length of the bridgeboard, the measuring interval and the straightness of the guide. A straightness calculation model is also developed using the method, and the errors stemming from the method proposed are introduced in brief. A precision air-bearing guide with a long air-bearing bush is measured and evaluated using the method proposed, and the actual measurement and evaluation results prove that the method is correct in theory and practical in operation. The method proposed gives an effective and flexible solution to the straight-ness measurement of the precision guide with long slide-carriage or air-bearing bush in application. It is an extension of the traditional optical-electronic autocollimation
method for straightness measurement.
Key words:
Straightness measurement Optical-electronic autocollimator Alterable interval Autocollimation Air bearing guide Slide carriage
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