International comparison of roundness profiles with nanometric accuracy

Roundness profiles are compared which were obtained from measurements carried out at five national metrology laboratories. In the analysis, standard deviations and maximum deviations were calculated from point-by-point differences of the profiles with reference to one another or to the reference profile. Fourier analysis was used to select a spectral area for an analysis at the edge of the significance limit. The comparison shown that each participating laboratory is able to measure a roundness profile with a standard deviation in each data point of less than 2 nm.