접촉식 형상 측정기에 의한 표면 미세 형상 측정시 촉침 반경이 측정 오차에 미치는 영향

Abstract

This paper describes the effect of the stylus tip size on the measuring error in surface topography measurement. To analyze the distortional effect of an actual surface geometry originating from the finite stylus size, the surface is modeled as a sinusoidal and the stylus tip as a circle. The measuring error is defined as the ratio of the standard deviation of a tracing profile and an original profile. It is shown that this measuring error depends on the amplitude and wavelength of an original profile. In this paper, the spectrum analysis is applied to investigate the distortional effect due to the mechanical filtering of the stylus in the frequency domain. and, the cumulative power spectrum is applied to determinate the minimum wavelength limits to be measured with the various stylus tip radius. From these results, a new method to select proper stylus tip radius is proposed.