Dependence of measuring errors of rms roughness on stylus tip size for mechanical profilers

Tracing of a random profile with a mechanical profiler with a spherical tipped stylus has been investigated by means of computer simulation. It is shown that the fractional measuring errors of rms roughness depend on only the ratio of rms roughness varsigma to the stylus tip radius r and the ratio of rms roughness to the 1/e correlation length rho(c). The ratios varsigma/r were in the range of 0.005-0.05 and the ratios varsigma/rho(c) were equal to 0.028 and 0.048.