Issues in Laser Step Diagonal Measurement and Their Remedies
Soichi Ibaraki, Wataru Goto, Atsushi Matsubara
Abstract
The laser step diagonal measurement modifies the diagonal displacement measurement by executing a diagonal as a se-quence of single-axis motions. It has been claimed that it en-ables the identification of all the volumetric error components including linear errors, straightness and squareness errors. In this paper, we show that the conventional formulation of the step diagonal measurement is valid only when implicit assump-tions related to the configuration of laser and mirror setups are met, and that its inherent problem is that it is generally not pos-sible to meet these conditions by the adjustment of the setup. To address this problem, we propose a new formulation of the step diagonal measurement, in order to accurately identify volumetric errors even under the existence of setup errors. The effectiveness of the proposed modified identification scheme is investigated experimentally by an application example to a high-precision machine tool.
Key Words: Step-diagonal measurement, volumetric errors, machine tool, laser interferometer.
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