COMPLEMENTING AND ENHANCING DEFINITIONS OF LINE PROFILE COMPOSITE TOLERANCE IMPOSED BY ISO GEOMETRICAL PRODUCT SPECIFICATION

Abstract

According to the ISO Geometrical Product Specifications (GPS), if two or more specifications of the same characteristic are to be indicated, they may be combined as a composite tolerance. Therefore there are no definition differences between the single separate tolerance indicators and their composite tolerance, which is different from the ASME standards. Hereby, the definitions of the combined tolerance which specifies the additional location, orientation and form of tolerance zone are not explicitly defined in the current ISO. It restricts the required definitions of tolerance specifications of a component which are often utilized in practice. However, the required definitions cannot be notated in the technical drawings by using the ISO semantics, because the ISO definitions are insufficient. It causes definition gaps and misinterpretations. This paper focuses on developing the definitions of line profile composite tolerance and suggests a new approach for explicitly defined and function-oriented systematology of line profile composite tolerance. This research is based on the analysis of physical behaviour of geometric feature of a component on a theoretical level. Completed and enhanced definitions in an improved systematology for line profile composite tolerance is formulated which fills the definition gaps and eliminates the deficits in ISO GPS.