A method for evaluation of elliptical profiles

Abstract Measurement and evaluation of circular profiles of cylindrical components in terms of circularity has been well established using roundness measuring instruments. For elliptical sections having very little difference between the major and minor diameters this difference can be measured with the roudness measuring instrument. However, fitting of the best fit ellipse and hence the definition of ellipticity are not available. Applications of elliptical profiles include instruments, such as the photospectrometer developed at CMTI with accurate elliptical cams, elliptical gear blanks, and the pistons of internal combustion engines whose cross sections are elliptical. In this paper a method for the evaluation of the elliptical profiles for centre and orientation of major and minor axes is described and two concepts for defining ellipticity are discussed