Can ISO GPS and ASME Tolerancing Systems Define the Same Functional Requirements?

Zbigniew Humienny

doi:10.3390/app11178269

Abstract

Geometrical tolerances are defined in the ISO Geometrical Product Specification system that is used worldwide, but on the other hand, the ASME Y14.5 standard is used in American companies to define how far actual parts may be away from their nominal geometry. This paper aimed to investigate whether specifications defining acceptable geometrical deviations in one system can be transformed to specifications in the other system. Twelve selected cases are discussed in the paper. Particularly, two cases of size tolerance, three cases of form tolerances, one case of orientation tolerance, four cases of position tolerance (including position tolerance with MMR for the pattern of five holes) and, finally, two cases of surface profile tolerance (unequally disposed tolerance zone and dynamic profile tolerance). The issue is not only in the several different symbols and a set of different defaults, but also in the different meanings and different application contexts of some symbols that have the same graphical form. The answer to the question raised in the paper title is yes for the majority of indications specified according to ASME Y14.5 when new tools from the 2017 edition of ISO 1101 are applied.

Highlights

Manufacturing metrology covers verification of whether produced parts fulfil functional requirements defined by a customer
The geometrical product specification and verification system developed in ISO by Technical Committee ISO/TC 213 (ISO GPS system) [5] is a set of concepts, principles, rules and symbols that enable description and clarification of how far geometrical features of an actual workpiece can be away from theoretically exact geometry (CAD model of a part) [6,7,8,9,10,11]
It should be noted that transformation from ASME Y14.5 to the ISO GPS notation without loss of the part’s intended function may be performed in a significantly larger amount of cases than reverse conversion due to a new set of modifiers implemented in ISO 1101:2017 [7]

Summary

Introduction

Manufacturing metrology covers verification of whether produced parts fulfil functional requirements defined by a customer. It should be noted that transformation from ASME Y14.5 to the ISO GPS notation without loss of the part’s intended function (loss of coded information) may be performed in a significantly larger amount of cases than reverse conversion due to a new set of modifiers implemented in ISO 1101:2017 [7] It was underlined in [2] that. Sci. 2021, 11, 8269 to the ISO GPS notation without loss of the part’s intended function (loss of coded information) may be performed in a significantly larger amount of cases than reverse con3voefr-21 sion due to a new set of modifiers implemented in ISO 1101:2017 [7] It was underlined in [2] that ISO 1101:2017 allows for more precise tolerance definitions that are independent oIfStOhe1v1i0e1w:2p01la7naellaonwdsaflosor msuoprpeoprtredciigsietatol ltehrraenacdes dfoerfigneitoimonestrtyhatssaurerainncdee.pOennedhenutnodfrethde anvidewfiftpylaInSeOadnodcualmsoensutsp[p5o] rctudrrigeinttallythforremadtshfeorISgOeoGmPeStrsyysatsesmur,abnucteo.

ISO GPS Identical Graphical Indication

Conclusions