Linear Sizes

Abstract

In the past, the verification of the local size of workpieces was carried out using traditional metrological instruments, such as callipers and micrometres, or using hard gauges to check for conformance with the global size tolerances. Today, in order to remove any ambiguities that existed in the traditional size tolerance specifications, it is necessary to both exploit the benefits of CMMs and other coordinate measuring systems that collect several points from the surface of a feature and, at the same time, to expand the concept of size tolerancing in order to communicate the function of a part more clearly. The specification operators defined in the ISO 14405 standards provide mechanisms that can be used to expand the domain of size specifications by means of a rich, new set of size modifiers, which provide new capabilities that can be used to address the requirements that arise from many industrial applications.