Calibration services of 5 countries from the SIM region are compared through measurements of surface roughness and step height standards. A surface roughness standard with a nominal Ra value of 0.2 mm, a surface roughness standard with a nominal Ra value of 3 mm and a nominal spatial wavelength of 99 mm, and three step height standards with nominal values of 2.55 mm, 0.38 mm and 0.03 mm are compared. Special attention is paid to the influence of the cut-off ratio of the measurements. The initial reported results show that the laboratories agree on all of the measurements within their stated and published uncertainties. Observations are then discussed about the definition of Rz, the effect of instrument noise on Rz, the different step height parameters d and Pt, differences between the laboratories in reporting Type A statistical uncertainties, and the use of exclusive statistics to determine degree of equivalence. After corrections and reanalysis the laboratories still agree well considering their stated uncertainties.
Pub Type: Journals
comparison, finish, metrology, Ra, roughness, RSm, Rz, step height, stylus