Sampling Interval Selection for 3D Surface Roughness Measurements Using the Contact Method

The article presents the impact of sampling interval ΔX=ΔY upon the precision of parametrical assessment of roughness of selected surfaces. Moreover this study introduces theoretical analysis of sampling interval selection based on analysis of the probability of covering an unordered set of extreme points of surface with an ordered set of measurement points. As the result, the final formula was formulated, which enables to calculate the maximum sampling rate ΔX=ΔY. This guarantees a full 100% coverage of the vertices examined by the unevenness of the measuring grid