Abstract: In order to clarify the validity of the method of root mean square measurement(RMSM) for fractal characterization of surfaces, a set of surfaces with different roughness are processed by turning, milling, grinding and rubbing, and their fractal characterizations are performed with the RMSM method and the structure function measurement(SFM) method for comparing. The results show that RMSM method has the characteristics as follows: wider range of scale invariance and better linearity of fractal characterization curves to make it more accurate; less dependent on sampling frequency and nonvolatility of fractal information during fractal calculation to be more objective; and definite physical meanings and simple fractal characterization to become easier. The RMSM is a valid method for fractal characterization of machined surfaces.

Key words: Machined surface, Fractal characterization, Root mean square measurement, Structure function measurement