Surface Roughness Measuring Based on the Theory of Fractal Geometry

Abstract

Conventionally several statistical roughness parameters are used for describing surface roughness. But instruments with different resolutions and scan lengths yield different results of these statistical parameters for the same surface. Due to the limitations of traditional characterizing methods, the fractal characteristic of the rough surface is studied in this paper. A surface roughness measuring instrument is redesigned based on the on theTalysurf5Μ for both hardware and software. The signal conditioning process of the inductance sensor is analyzed. The grinding samples measurements indicate that work-piece surface presents fractal characteristic, and larger roughness level Ra corresponds to larger fractal dimensionDbut smaller characteristic length scaleG. The fractal characterization of surface roughness, to some extent, overcomes the deficiencies of conventional evaluation method, and shows higher sensitivity and accuracy.