Substitute Geometry of Multidimensional Features
Vladimir T. Portman · ASME Press eBooks · 2019
Synthesis of the substitute feature (SF) is shown in the previous chapter to be a necessary step in building the tolerance zone for standard assessment of geometric accuracy [1–3]. Since the SF must be of perfect form, its synthesis uses information about the nominal feature (NF) and includes the deviations leaving the feature shape unchanged – the size, position, and orientation deviations (SPOD). Evaluation of the SF parameters is carried out using the actual feature (AF) data resulting from the point-to-point coordinate measurements of the AF on coordinate measuring machines (CMM). Thus, the SF concentrates the information needed for verification of the manufactured workpiece – information about the NF from the drawing and information about the AF in the form of results of measurements.