SIST EN ISO 21204:2020

Geometrical product specifications (GPS) - Transition specification (ISO 21204:2020)

A transition is an areal feature connecting two adjacent features, for which the intersection is a line. The transition includes portions of the adjacent features. This document defines a number of specification operators for the specification of defined transitions. These specifications all apply to any line in a defined direction in the transition feature. It also defines the specification modifiers and the drawing indications for such transition specifications.
The proportions and dimensions of the graphical symbols to be used are also specified.
This document provides a set of tools to express several defined transition specifications. It does not present any information on the relationship between a function or a use and a defined transition specification.

Geometrische Produktspezifikation (GPS) - Spezifikation von definierten Übergängen zwischen Geometrieelementen (ISO 21204:2020)

Dieses Dokument legt eine Reihe an Spezifikationsoperatoren für die Spezifikation von erweiterten Kanten-übergangselementen zwischen Geometrieelementen fest. Ein Kantenübergangselement ist ein integrales Element, über das zwei angrenzende integrale Geometrieelemente verbunden sind. Das erweiterte Kanten¬übergangselement beinhaltet Teile der angrenzenden Geometrieelemente. Alle diese Spezifikationen gelten für alle Geraden in einer definierten Richtung in dem erweiterten Kantenübergangselement. Dieses Dokument definiert zudem die Spezifikations-Modifikationssymbole und die Zeichnungsangaben für solche Übergangs¬spezifikationen.
Die Proportionen und Maße der zu verwendenden graphischen Symbole sind ebenfalls angegeben.
Die in diesem Dokument definierten Spezifikationen sind für relativ einfache Kantenübergangsfunktionen geeignet, z. B. zum Sicherstellen der Montage ohne Störung. Für komplexere Funktionen bietet die geo-metrische Tolerierung präzisere Werkzeuge.
Dieses Dokument beschränkt sich bewusst nur auf Kantenübergangselemente zwischen zwei Ebenen und zwischen einem Zylinder und einer zu ihm nominell senkrechten Ebene.
Anhang A bietet den ersten Ansatz für einen Algorithmus zur Identifizierung von tolerierten Geometrie-elementen und angrenzenden Referenzabschnitten. Dieser Algorithmus kann jederzeit aktualisiert werden, falls neue Informationen vorliegen.
Dieses Dokument stellt mehrere Werkzeuge zur Angabe mehrerer Übergangsspezifikationen zur Verfügung. Es liefert keine Informationen über die Beziehung zwischen einer Funktion oder einer Verwendung und einer Übergangsspezifikation.
ANMERKUNG 1   Ecken (der Übergang zwischen drei oder mehr Geometrieelementen) sind keine Kantenübergangs-elemente und werden daher in diesem Dokument nicht berücksichtigt.
ANMERKUNG 2   Ein Kantenübergangselement ist zwischen zwei einzelnen Geometrieelementen vorhanden. Ein definiertes Kantenübergangselement besitzt eine definierte nominale Gestalt und ist nicht scharf (r = 0).

Spécifications géométriques des produits (GPS) - Spécification de transition (ISO 21204:2020)

Le présent document définit un certain nombre d'opérateurs de spécification pour la spécification des éléments de transition d'arête étendue entre des éléments. Un élément de transition d'arête est un élément intégral qui relie deux éléments intégraux adjacents. L'élément de transition d'arête étendue inclut des portions des éléments adjacents. L'ensemble de ces spécifications s'appliquent à n'importe quelle ligne suivant une direction définie dans l'élément de transition d'arête étendu. Le présent document définit également les modificateurs de spécification et les indications sur le dessin relatives aux spécifications de transition.
Il spécifie également les proportions et dimensions des symboles graphiques à utiliser.
Les spécifications définies dans le présent document s'appliquent à des fonctions de transition d'arête relativement simples, par exemple pour garantir un assemblage sans interférence. Pour des fonctions plus complexes, un tolérancement géométrique offre des outils plus précis.
De par son intention, le présent document est limité aux seuls éléments de transition d'arête entre deux plans et entre un cylindre et un plan qui lui est nominalement perpendiculaire.
L'Annexe A décrit la première approche d'un algorithme permettant d'identifier les éléments tolérancés et les sections de référence adjacentes. Cet algorithme est susceptible d'évoluer au fil des expérimentations.
Le présent document fournit un ensemble d'outils visant à exprimer plusieurs spécifications de transition. Il ne donne aucune information sur la relation entre une fonction ou une utilisation et une spécification de transition.
NOTE 1    Les angles (la transition entre au moins trois éléments) ne sont pas des éléments de transition d'arête et ne sont donc pas couverts par le présent document.
NOTE 2    Il existe un élément de transition d'arête entre deux éléments simples. Un élément de transition d'arête défini possède une forme nominale définie et n'est pas vif (r = 0).

Specifikacije geometrijskih veličin izdelka (GPS) - Specifikacija prehoda (ISO 21204:2020)

General Information

• Status: Published
• Public Enquiry End Date: 31-Oct-2017
• Publication Date: 06-Apr-2020
• ICS: 17.040.40 - Geometrical Product Specification (GPS)
• Technical Committee: ISEL - Mechanical elements
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 30-Mar-2020
• Due Date: 04-Jun-2020
• Completion Date: 07-Apr-2020
• Ref Project: EN ISO 21204:2020 - Geometrical product specifications (GPS) - Transition specification (ISO 21204:2020)

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 21204:2020
01-junij-2020
Specifikacije geometrijskih veličin izdelka (GPS) - Specifikacija prehoda (ISO
21204:2020)
Geometrical product specifications (GPS) - Transition specification (ISO 21204:2020)
Geometrische Produktspezifikation (GPS) - Spezifikation von definierten Übergängen
zwischen Geometrieelementen (ISO 21204:2020)
Spécifications géométriques des produits (GPS) - Spécification de transition (ISO
21204:2020)
Ta slovenski standard je istoveten z: EN ISO 21204:2020
ICS:
17.040.40 Specifikacija geometrijskih Geometrical Product
veličin izdelka (GPS) Specification (GPS)
SIST EN ISO 21204:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 21204:2020

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SIST EN ISO 21204:2020


EN ISO 21204
EUROPEAN STANDARD

NORME EUROPÉENNE

March 2020
EUROPÄISCHE NORM
ICS 17.040.01
English Version

Geometrical product specifications (GPS) - Transition
specification (ISO 21204:2020)
Spécifications géométriques des produits (GPS) - Geometrische Produktspezifikation (GPS) -
Spécification de transition (ISO 21204:2020) Spezifikation von definierten Übergängen zwischen
Geometrieelementen (ISO 21204:2020)
This European Standard was approved by CEN on 16 February 2020.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21204:2020 E
worldwide for CEN national Members.

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SIST EN ISO 21204:2020
EN ISO 21204:2020 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 21204:2020
EN ISO 21204:2020 (E)
European foreword
This document (EN ISO 21204:2020) has been prepared by Technical Committee ISO/TC 213
"Dimensional and geometrical product specifications and verification" in collaboration with Technical
Committee CEN/TC 290 “Dimensional and geometrical product specification and verification” the
secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by September 2020, and conflicting national standards
shall be withdrawn at the latest by September 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 21204:2020 has been approved by CEN as EN ISO 21204:2020 without any modification.


3

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SIST EN ISO 21204:2020

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SIST EN ISO 21204:2020
INTERNATIONAL ISO
STANDARD 21204
First edition
2020-02
Geometrical product specifications
(GPS) — Transition specification
Spécifications géométriques des produits (GPS) — Spécification de
transition
Reference number
ISO 21204:2020(E)
©
ISO 2020

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SIST EN ISO 21204:2020
ISO 21204:2020(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

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ISO 21204:2020(E)

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Basic concepts . 2
5 General indication rules . 4
5.1 Symbols . 4
5.2 Indications using the transition specification symbol . 5
5.2.1 General. 5
5.2.2 Indications in face view . 6
5.2.3 Indications in 3D . 6
5.3 Indication areas around the transition specification symbol . 7
6 Circular edge transition feature indications . 7
6.1 Fixed radius profile specification . 7
6.2 Variable radius profile specification . 8
6.3 Consistent radius profile specification . 9
6.4 Maximum material radius boundary specification.10
6.5 Least material radius boundary specification .10
6.6 Maximum material radius boundary with profile specification .11
6.7 Least material radius boundary with profile specification .12
6.8 Combined maximum material and least material radius boundary specification .13
7 Chamfer edge transition feature indications .14
7.1 Fixed chamfer profile specification .14
7.2 Variable chamfer profile specification .17
7.3 Consistent chamfer profile specification .18
7.4 Maximum material chamfer boundary specification .19
7.5 Least material chamfer boundary specification .20
7.6 Maximum material chamfer boundary with profile specification .21
7.7 Least material chamfer boundary with profile specification .22
7.8 Combined maximum material and least material chamfer boundary specification .23
8 Elliptical edge transition feature indications .24
8.1 Fixed elliptical profile specification .24
8.2 Variable elliptical profile specification .25
8.3 Consistent elliptical profile specification .26
8.4 Maximum material elliptical boundary specification .26
8.5 Least material elliptical boundary specification .27
8.6 Maximum material elliptical boundary with profile specification .28
8.7 Least material elliptical boundary with profile specification.29
8.8 Combined maximum material and least material elliptical boundary specification .30
9 Edge transition feature defined by CAD .31
9.1 CAD profile specification .31
9.2 Maximum material CAD profile boundary specification .32
9.3 Least material CAD profile boundary specification .33
9.4 Maximum material CAD profile boundary with profile specification .34
9.5 Least material CAD profile boundary with profile specification .35
10 Rules for supplemental indications .36
10.1 Symbols .36
10.2 Limits of different nominal shapes .36
10.3 Extent of the toleranced feature.37
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10.4 Tolerance zone offset .37
10.5 Indication of primary adjacent reference section . .38
10.6 Indication of several toleranced features .38
10.7 Indications using the between symbol .38
10.8 Around a feature indications .39
10.9 General transition specifications .40
Annex A (informative) Algorithm for defining extended edge transition sections and
adjacent reference sections .41
Annex B (informative) Example of approximately equivalent specification of extended edge
transition features .48
Annex C (normative) Relations and dimensions of graphical symbols .50
Annex D (informative) Relation to the GPS matrix model .51
Bibliography .52
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SIST EN ISO 21204:2020
ISO 21204:2020(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 213, Dimensional and geometrical product
specifications and verification, in collaboration with the European Committee for Standardization (CEN)
Technical Committee CEN/TC 290, Dimensional and geometrical product specification and verification, in
accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
© ISO 2020 – All rights reserved v

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ISO 21204:2020(E)

Introduction
This document is a geometrical product specification (GPS) standard and is to be regarded as a general
GPS standard (see ISO 14638). It influences chain links A, B and C of the chains of standards on form,
orientation and location, see Annex D.
The ISO GPS matrix model given in ISO 14638 gives an overview of the ISO GPS system of which this
document is a part. The fundamental rules of ISO GPS given in ISO 8015 apply to this document and
the default decision rules given in ISO 14253-1 apply to specifications made in accordance with this
document, unless otherwise stated.
In technical drawings, the ideal geometric shape of the workpiece is represented without any deviations
and, in general, without consideration of the states of the transitions between adjacent integral
features. Nevertheless, for many purposes (the functioning of a part, or out of safety considerations, for
example) particular states of transition features need to be indicated. ISO 13715 provides the tools for
indicating requirements to edges of undefined shape. These tools are insufficient when the shape of the
transition feature is important for functional reasons. Therefore, this document provides a set of tools
for indicating transition specifications.
IMPORTANT — Most specification illustrations in this document show edges drawn as sharp corners.
They could equally have been drawn showing the nominal geometry of the transition feature, without
changing the meaning of the indications. In a computer aided design (CAD) system, the transition
feature geometry can be modelled or not without changing the meaning of the indications.
All the specification illustrations in this document show a 90° angle between the two adjacent features.
Specifications according to this document have the same meaning, taking the nominal angle into
account, regardless of the angle between the two adjacent features.
All figures in this document have been drawn with dimensions and tolerances in millimetres. It should
be understood that other units of measurement could have been used equally well without prejudice to
the principles established.
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SIST EN ISO 21204:2020
INTERNATIONAL STANDARD ISO 21204:2020(E)
Geometrical product specifications (GPS) — Transition
specification
1 Scope
This document defines a number of specification operators for the specification of extended edge
transition features between features. An edge transition feature is an integral feature connecting
two adjacent integral features. The extended edge transition feature includes portions of the adjacent
features. All these specifications apply to any line in a defined direction in the extended edge transition
feature. This document also defines the specification modifiers and the drawing indications for such
transition specifications.
The proportions and dimensions of the graphical symbols to be used are also specified.
The specifications defined in this document are suitable for relatively simple edge transition functions,
for example ensuring assembly without interference. For more complex functions, geometrical
tolerancing offers more precise tools.
This document is by intention limited to only edge transition features between two planes and between
a cylinder and a plane nominally perpendicular to it.
Annex A gives the first approach for an algorithm to identify toleranced features and adjacent reference
sections. This algorithm is subject to change as more experience is gathered.
This document provides a set of tools to express several transition specifications. It does not present
any information on the relationship between a function or a use and a transition specification.
NOTE 1 Corners (the transition between three or more features) are not edge transition features and are
consequently not covered by this document.
NOTE 2 An edge transition feature exists between two single features. A defined edge transition feature has a
defined nominal shape and is not sharp (r = 0).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1101:2017, Geometrical product specifications (GPS) — Geometrical tolerancing — Tolerances of form,
orientation, location and run-out
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
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ISO 21204:2020(E)

3.1
transition feature
single integral feature connecting two or more adjacent integral surfaces
Note 1 to entry: A single integral feature connecting three or more adjacent integral surfaces (corner) is not
covered in this document.
3.2
edge transition feature
single integral feature connecting two adjacent integral surfaces
3.3
extended transition feature
collected integral surface including a transition feature and specified contiguous portions of the
adjacent features
3.3.1
extended edge transition feature
collected integral surface including an edge transition feature and specified contiguous portions of the
adjacent features
3.3.1.1
extended edge transition section
line resulting from the intersection of an extended edge transition feature with a specified plane
3.4
transition specification
GPS requirement applied to an extended transition feature
3.5
reference portion
line segment in an adjacent feature beyond the extended edge transition section
3.6
adjacent reference section
straight line associated to a reference portion
Note 1 to entry: An adjacent reference section is used as a datum in a transition specification.
3.7
separation point
point separating the search areas for finding the ends of the adjacent features
3.8
specification origin
intersection point between two straight lines established from the adjacent surfaces in an intersection
plane defined in a specified direction
Note 1 to entry: See Figure A.4.
3.9
specification direction
direction in which one of the distances defining the toleranced feature and the reference portion applies
4 Basic concepts
An edge transition feature is an areal feature.
Specifications for edge transition features according to this document specify either extended edge
transition sections defined in a specified set of intersection planes, where the specification for each
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ISO 21204:2020(E)

section is independent of the other sections, or collections of such sections, for example a requirement
that the radius shall be consistent along the edge transition feature.
By default, transition specifications apply to all extended edge transition sections along the extended
edge transition feature.
Figure 1 shows the case where the two adjacent features are planes. The intersection planes that defines
the toleranced features are in theoretically exact relationships to the situation feature (straight line) of the
collection of associated features adjacent to the edge transition feature. The associations are performed
individually to each adjacent feature with the total least squares (Gaussian) criterion. The intersection
planes are perpendicular to the intersection straight line between the two associated planes.
The length of the toleranced extended edge transition feature is limited as proposed in A.3.
Key
1 nominally flat real features adjacent to the edge transition feature
2 total least squares (Gaussian) planes associated to 1 independently
3 intersection straight line between 2
4 one of the infinite set of intersection planes perpendicular to 3
5 one of the infinite set of line profiles containing a toleranced extended edge transition section
Figure 1 — Intersection planes defining the toleranced features for an edge transition feature
between two planar features
Figure 2 shows the case where one adjacent feature is a plane and the other is a cylinder. In this case
the associations are performed simultaneously to the two adjacent features with the constraint that
the associated features are perpendicular to each other, like a common datum, but with the total least
squares (Gaussian) criterion. The intersection plane contains the axis of the associated cylinder and is
also by definition perpendicular to the associated plane.
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ISO 21204:2020(E)

Key
1 nominally flat real feature adjacent to the edge transition feature
2 nominally cylindrical real feature adjacent to the edge transition feature
3 total least squares (Gaussian) cylinder associated to 2
4 axis of 3
5 one of the infinite set of intersection half planes including 4
6 one of the infinite set of line profiles containing a toleranced extended edge transition section
Figure 2 — Intersection planes defining the toleranced features for an edge transition feature
between a planar feature and a cylindrical feature
The figures given in Clauses 6 to 9 are not intended to describe the partition. The process of the
partitioning of the extended edge transition feature is illustrated in Annex A.
The extent of the reference portions is limited as proposed in A.3. This means that the real surface
of the workpiece beyond this extent does not influence the location and orientation for the adjacent
reference sections and that material constraints only apply within the defined extent, see, for example,
Figure 12 b) where the material constraint does not apply beyond the extent of the reference portion.
If the intersection between the intersection plane and the adjacent feature is not nominally straight,
a suitable shape, for example a circle, shall be associated instead with the relevant shape and size
parameters being variable in the association, see A.1.
Adjacent reference sections are associated to the reference portions of the adjacent featur
...