A software-based relocation technique for surface asperity profiles and its application to calculate volume changes in running-in wear

Evaluation of truncated surface asperities is critically important in many industrial applications. Any discussion of truncation processes such as wear mechanisms and plateau honing requires a comparison of the original profile with the truncated one. In order to compare profiles, it is necessary to accurately relocate the truncated profile with respect to the original one. However, there is a limitation to relocation using hardware. To achieve accurate relocation, the authors propose a software-based relocation technique. In this paper, we present newly two software-based relocation techniques that examine the correspondence between untruncated areas in the truncated profile and the same untruncated areas in the original profile. In the first technique, the correspondence is measured by a collation index that is determined for the two profiles and calculated in an optimization method. In the second technique, the height probability distributions of two profiles are calculated and the profiles are then relocated in order to obtain the minimum degree of difference. Furthermore, the applicability of these techniques is discussed using simulation data and actual measurement data. These techniques are effective in the range that the truncated surface height is higher than −1.28σo (σo is the standard deviation of untruncated original surface height) from experiment, and are useful for measuring very little wear volume changes in contrast with measuring mass changes.