Characterization of surface roughness – T.R. Thomas 

Abstract

Proliferation of redundant parameters for characterizing surface roughness is explained as a historical consequence of the predominant influence of instrument manufacturers over users. Problems of roughness characterization are introduced: high and low-pass filtering, transitional topographies, sampling error. The needs of three classes of user, the machinist, the researcher and the quality control engineer, are discussed. Three kinds of descriptor, namely statistical height, extreme-value height and texture are identified, and examples of each are defined are critically compared, with appliations. It is suggested that a classification comprising average roughness, skewness, high-spot count and extrema density might suffice for many engineering purposes