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Complements and Enhancements of Position Tolerance for Axis and Derived Line Imposed by ISO Standards

Yiqing Yan and Martin Bohn
Dimensional Management, Research & Development, Mercedes-Benz Cars, Daimler AG, Sindelfingen, Germany

Abstract— According to the ISO Geometrical Product Specification (GPS), position tolerance can be used to specify axis and derived line in 2D technical drawings by using a diameter symbol within a perpendicular datum system. For an axis which is inclined inset of a component surface without diameter symbol in a non-perpendicular datum system in a 3D tolerancing, is not explicit explicated and lack of examples in ISO GPS standards. Moreover, there exists a contraction by using position tolerance for derive line inside of ISO standards. It causes incomprehension, ambiguous interpretations and definition gaps by using the position tolerance in practice. This paper suggests a new approach for establishing a holistic systematology with explicit defined definitions and examples of position tolerance to complete and enhance the ISO standards. This research is based on the analysis of function-oriented physical behavior of axis and derived line of a component on a theoretical level. An improved systematology for a functional explicit definition of position tolerance is formulated which eliminates the deficits of ISO GPS. 

Index Terms— Position tolerance, geometrical product specification, tolerancing and dimensioning, ISO standards, 3D tolerancing

Cite: Yiqing Yan and Martin Bohn, "Complements and Enhancements of Position Tolerance for Axis and Derived Line Imposed by ISO Standards," International Journal of Mechanical Engineering and Robotics Research, Vol. 7, No. 2, pp. 158-163, March 2018. DOI: 10.18178/ijmerr.7.2.158-163