APPLICATION OF T-MAPS FOR COMPOSITE POSITION TOLERANCE FOR PATTERNS OF FEATURES

The purpose of this paper is to develop Tolerance Maps (T-Maps) for composite position tolerance applied to patterns (arrays) of features. The T-Map (Patent No. 6963824), is a range of points obtained by mapping all the variational possibilities of a feature within its tolerance-zone to a hypothetical Euclidean point space. T-Maps have already been developed for tolerances applied to features, such as a simple axis (line), a plane, a cylinder, etc., but not for patterns of features. In this paper, the developed T-Map model will be shown to be sensitive to the effects of composite position tolerance, two-single segment control frames and material modifiers. Two levels of T-Maps are proposed for a pattern of features: assembly level (ensuring assembly of engaging pattern of features) and part level (map of variations of entire pattern as a whole). The use of assembly level and part level T-Map is demonstrated with a pattern of features. The pattern of features considered is two-dimensional patterns of pins and holes that are intended to engage (e.g. an integrated circuit and its plug-in base).