Measurement method for the eccentricity of an off-axis asphere with a laser tracker

Ruigang Li

doi:10.3788/COL201513.S22206

Chinese Optics Letters, Volume. 13, Issue Suppl., S22206(2015)

Measurement method for the eccentricity of an off-axis asphere with a laser tracker

Ruigang Li^*

Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics, and Physics, Chinese Academy of Sciences, Changchun 130033, China

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Figures & Tables(5)

Fig. 1. Schematic of null compensating interferometry.

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Fig. 2. Diagram of the testing procedure.

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Fig. 3. Sketch of the eccentricity measurement layout.

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Fig. 4. Photograph of an eccentricity measurement.

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Table 1. Uncertainty Analysis

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Table 1. Uncertainty Analysis

Item	Error	Remark
Cylindricity of Compensator	$e_{1} < 0.0100 mm$
Eccentricity of Compensator	$e_{2} < 0.0100 mm$
Deflection of Compensator	$< 5^{''}$ , so $e_{3} < L * \tan (5^{''}) = 0.1818 mm$
Flatness of Asphere	$e_{4} < 0.0100 mm$
Laser Tracker	Distance accuracy: $e_{5} = 2 μm + L * 0.4 μm / m = 0.0050 mm$ ; Angle accuracy: $e_{6} = 10 μm + L * 2.5 μm / m = 0.0288 mm$	FARO (ION), interferometer), distance accuracy and angle accuracy are all typical values
Total	$e = \sqrt{Σ_{i = 1}^{6} e_{i}^{2}} = 0.1859 mm$	Root-sum squared (RSS) of individual errors.