CONCEPTS, PRINCIPLES AND RULES IN THE ISO GPS SYSTEM – RELATIONS, COHERENCES AND INCOHERENCES

Abstract

The ISO/TC 213 Technical Committee works on the coherent and systematic development of international standards covering the issues of dimensioning, geometrical tolerancing, surface texture, and metrology. The development of the ISO GPS standards has resulted in the publishing of almost 150 standards. The main task of the committee is to develop new standards with a strong emphasis on their unambiguity and consistency, however, the Committee has not always succeeded in preserving these goals. A brief review of the following set of standards: ISO 8015, ISO 17450 series, ISO 22432, ISO 25378 and ISO 14638, by ISO/TC 213 experts forced Working Group 14 (Vertical GPS Principles) to consider actions related to the in-depth revision of these standards’ structure and content. Several inconsistencies were discovered, and the issue of the standards' incoherence has emerged as much more serious than it first appeared. To initiate the work, the authors were asked by WG 14 to find and determine relationships between such fundamental expressions as concept, principle, rule, and term, the usage of which in the standards seems to be inconsistent. However, due to the current standards' structure and content, the authors have encountered problems in clearly identifying these expressions, which make relationship analysis very difficult. This paper discusses the inconsistencies and findings mentioned above. Due to the wide application of the ISO geometrical product specification system (geometrical tolerancing system) in the automotive and aviation industries, this paper aims to highlight the problems experienced by practitioners. Finally, significant changes regarding the approach to the structure of standards are proposed and discussed.