The transition of two geometrical features, like a radius or edge, is one part of the geometrical properties of a workpiece. For abrasive flow machining as a surface finishing process the characterization of the edge is important. Different processing parameters of the abrasive flow machining process are compared to geometrical properties within a test series. Based on 3D measurements and a datum system first results of an edge definition are derived. A histogram of radii provides a simplified method to separate the geometrical features to define the start and end of the edge.

For technical surfaces, it is important to know their functional purpose and to characterize them accordingly. Therefore, ISO 21920-2 in 2D and ISO 25178-2 in 3D offer parameters that can assess surface functional properties. The topographic portions of a surface, for example hills and dales, can be classified as features and evaluated using feature parameters. However, no parameter exists to describe the spatial distribution of features with regard to the degree of homogeneity for aperiodic surfaces. Here we show the application of the Delaunay triangulation to quantify the spatial distribution respectively the geometric relationship of features. Therefore, the feature points are determined by watershed analysis and the resulting point cloud is meshed in 2D. Based on that mean and standard deviation of the triangle side lengths and the area disorder (AD) are calculated as new parameters. The method is demonstrated for sandblasted and chrome-plated specimens. In addition simulation is used to generate more data for analysis. With the proposed approach the distinction and extent of uniform, homogeneous or inhomogeneous spatial distributions of features with parameter AD can be determined.