Influence of Surface Slope on the Roughness Measurement

International standars prescribe procedures for the computation of roughness parameters assuming the surfaces almost plane and perpendicular to the axis of deflection of the instrument stylus. The availability of new measuring instruments, characterised by larger ranges, permits to analyse geometries with important slopes. This paper discusses the errors occuring by the adoption of the conventional measuting techniques when oblique surfaces are examined and proposes a modification of the standard procedure in order to obtain correct results