SIST EN ISO 21920-1:2022
(Main)Geometrical product specifications (GPS) - Surface texture: Profile - Part 1: Indication of surface texture (ISO 21920-1:2021)
Geometrical product specifications (GPS) - Surface texture: Profile - Part 1: Indication of surface texture (ISO 21920-1:2021)
This document specifies the rules for indication of surface texture by profile methods in technical product documentation by means of graphical symbols.
This document does not cover population requirements.
NOTE See ISO 18391 for population (batch) specifications.
Geometrische Produktspezifikation (GPS) - Oberflächenbeschaffenheit: Profile - Teil 1: Angabe der Oberflächenbeschaffenheit (ISO 21920-1:2021)
Dieses Dokument legt Regeln für die Angabe der Oberflächenbeschaffenheit nach dem Tastschnittverfahren in der technischen Produktdokumentation mittels graphischer Symbole fest.
Dieses Dokument behandelt keine Populationsanforderungen.
ANMERKUNG Siehe ISO 18391 für Populationsspezifikationen.
Spécification géométrique des produits (GPS) - État de surface: Méthode du profil - Partie 1: Indication des états de surface (ISO 21920-1:2021)
Le présent document spécifie les règles d'indication des états de surface par des méthodes de profil dans la documentation technique des produits au moyen de symboles graphiques.
Le présent document ne couvre pas les exigences de population.
NOTE Voir la norme ISO 18391 pour les spécifications de la population (lot).
Specifikacija geometrijskih veličin izdelka (GPS) - Tekstura površine: profil - 1. del: Označevanje površinskih tekstur (ISO 21920-1:2021)
Ta dokument določa pravila za označevanje tekstur površine s profilnimi metodami v tehnični dokumentaciji izdelkov z grafičnimi simboli.
Ta dokument ne zajema zahtev glede populacije.
OPOMBA: Za populacijske (serijske) specifikacije glej standard ISO 18391.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-marec-2022
Nadomešča:
SIST EN ISO 1302:2004
Specifikacija geometrijskih veličin izdelka (GPS) - Tekstura površine: profil - 1. del:
Označevanje površinskih tekstur (ISO 21920-1:2021)
Geometrical product specifications (GPS) - Surface texture: Profile - Part 1: Indication of
surface texture (ISO 21920-1:2021)
Geometrische Produktspezifikation (GPS) - Oberflächenbeschaffenheit: Profile - Teil 1:
Angabe der Oberflächenbeschaffenheit (ISO 21920-1:2021)
Spécification géométrique des produits (GPS) - État de surface: Méthode du profil -
Partie 1: Indication des états de surface (ISO 21920-1:2021)
Ta slovenski standard je istoveten z: EN ISO 21920-1:2022
ICS:
17.040.20 Lastnosti površin Properties of surfaces
17.040.40 Specifikacija geometrijskih Geometrical Product
veličin izdelka (GPS) Specification (GPS)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 21920-1
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2022
EUROPÄISCHE NORM
ICS 17.040.40 Supersedes EN ISO 1302:2002
English Version
Geometrical product specifications (GPS) - Surface texture:
Profile - Part 1: Indication of surface texture (ISO 21920-
1:2021)
Spécification géométrique des produits (GPS) - État de Geometrische Produktspezifikation (GPS) -
surface: Méthode du profil - Partie 1: Indication des Oberflächenbeschaffenheit: Profile - Teil 1: Angabe der
états de surface (ISO 21920-1:2021) Oberflächenbeschaffenheit (ISO 21920-1:2021)
This European Standard was approved by CEN on 27 November 2021.
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
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21920-1:2022 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 21920-1:2022) 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 July 2022, and conflicting national standards shall be
withdrawn at the latest by July 2022.
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.
This document supersedes EN ISO 1302:2002.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
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 21920-1:2021 has been approved by CEN as EN ISO 21920-1:2022 without any
modification.
INTERNATIONAL ISO
STANDARD 21920-1
First edition
2021-12
Geometrical product specifications
(GPS) — Surface texture: Profile —
Part 1:
Indication of surface texture
Spécification géométrique des produits (GPS) — État de surface:
Méthode du profil —
Partie 1: Indication des états de surface
Reference number
ISO 21920-1:2021(E)
ISO 21920-1:2021(E)
© ISO 2021
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: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 21920-1:2021(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Tolerance acceptance rules .1
4.1 General . 1
4.2 Maximum tolerance acceptance rule . 2
4.3 16 % tolerance acceptance rule . 2
4.4 Median tolerance acceptance rule . 2
5 Specification elements for indication of profile surface texture specifications .3
5.1 General . 3
5.2 Mandatory indication to be explicitly specified . 3
5.3 Optional indications to specify non-default or further requirements . 3
6 Indication of profile surface texture .4
6.1 General . 4
6.2 Graphical symbols . 4
6.3 Minimal indication . 5
6.3.1 General . 5
6.3.2 Minimal indication for parameters with defined defaults. 5
6.3.3 Minimal indication for parameters without defined defaults . 5
6.4 Complete indication . 6
6.4.1 General . 6
6.4.2 Complete indication for evaluation length R-parameters . 7
6.4.3 Complete indication for section length R-parameters . 8
6.4.4 Complete indication for evaluation length P-parameters and W-parameters . 9
6.4.5 Complete indication for section length P-parameters and W-parameters . 10
7 Rules for indication of profile surface texture specifications .10
7.1 General . 10
7.2 Graphical symbol for the indication of profile surface texture specifications . 11
7.3 Profile surface texture parameter . 11
7.4 Tolerance limit value of the profile surface texture parameter . 11
7.5 Tolerance types . 11
7.6 Tolerance acceptance rule . 11
7.7 Profile S-filter type . 11
7.8 Profile S-filter nesting index . 11
7.9 Profile L-filter type (for R-parameter) or profile S-filter type (for W-parameter) .12
7.10 Profile L-filter nesting index (for R-parameter) or profile S-filter nesting index
(for W-parameter) . 12
7.11 Evaluation length .12
7.12 Section length . 12
7.13 Number of sections .12
7.14 Profile F-operator association method and element .12
7.15 Profile F-operator nesting index .12
7.16 Method of profile extraction .13
7.17 Other requirements, OR(n) .13
7.18 Manufacturing process .13
7.19 Surface lay and direction of lay . 13
7.20 Profile direction . 13
7.21 Setting class, Scn . 13
8 Position on technical product documentation .14
iii
ISO 21920-1:2021(E)
8.1 General . 14
8.2 Position and orientation of the graphical symbol . 14
9 Simplified and additional indications .17
9.1 Simplified indications . 17
9.1.1 General . 17
9.1.2 General tolerances . 17
9.1.3 Indication by the graphical symbol combined with a letter . 18
9.2 Restrictive specifications . 19
9.3 Indication of identical specifications for a number of feature elements .20
9.4 Indication of surface lay and direction of lay . 20
9.4.1 General .20
9.4.2 Indication of surface lay without a reference . 21
9.4.3 Indication of surface lay and direction of lay relative to a workpiece feature.22
9.5 Indication of the profile direction . 22
9.5.1 General .22
9.5.2 Indication of the profile direction relative to the predominant direction of
the surface lay . 23
9.5.3 Indication of the profile direction relative to a workpiece feature.23
9.6 Indication of bilateral surface profile tolerances . 24
9.7 Indication of different requirements for several additional processes on one
surface feature . . 24
Annex A (normative) Proportions and dimensions of graphical symbols .26
Annex B (normative) Filter symbols for profile surface texture .28
Annex C (normative) Symbols for association methods and association elements .29
Annex D (informative) Indications for unambiguous surface profile specification .30
Annex E (normative) Inspection procedure for the 16 % tolerance acceptance rule .43
Annex F (informative) Criteria for the use of the maximum tolerance acceptance rule as
the default . 44
Annex G (informative) New issues and changes to previous documents .45
Annex H (informative) Overview of profile and areal standards in the GPS matrix model .47
Annex I (informative) Relation to the GPS matrix model .48
Bibliography .49
iv
ISO 21920-1:2021(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).
This document cancels and replaces ISO 1302:2002, which has been technically revised. In addition to
the change of number, the main changes to ISO 1302:2002 are as follows:
— New specification elements for indication are defined.
— The maximum tolerance acceptance rule is the default tolerance acceptance rule.
A list of all parts in the ISO 21920 series can be found on the ISO website.
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.
v
ISO 21920-1:2021(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 link A of the chains of standards on profile surface
texture.
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 the specifications made in accordance with this
document, unless otherwise indicated.
For more detailed information of the relation of this document to other standards and the GPS matrix
model, see Annex H, Table H.1, and Annex I.
This document covers the indication of profile surface texture.
vi
INTERNATIONAL STANDARD ISO 21920-1:2021(E)
Geometrical product specifications (GPS) — Surface
texture: Profile —
Part 1:
Indication of surface texture
1 Scope
This document specifies the rules for indication of surface texture by profile methods in technical
product documentation by means of graphical symbols.
This document does not cover population requirements.
NOTE See ISO 18391 for population (batch) specifications.
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 21920-2, Geometrical product specifications (GPS) — Surface texture: Profile — Part 2: Terms,
definitions and surface texture parameters
ISO 21920-3, Geometrical product specifications (GPS) — Surface texture: Profile — Part 3: Specification
operators
ISO 81714-1, Design of graphical symbols for use in the technical documentation of products — Part 1:
Basic rules
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 21920-2 and ISO 21920-3
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/
4 Tolerance acceptance rules
4.1 General
Tolerance acceptance rules define how the tolerance limits are applied to the measured parameter
values. For profile surface texture, three tolerance acceptance rules can be indicated. See
ISO 21920-3:2021, Table 1 for the position of the measurements.
ISO 21920-1:2021(E)
4.2 Maximum tolerance acceptance rule
The maximum tolerance acceptance rule does not allow any measured value to exceed the tolerance
limit. The symbol of the maximum tolerance acceptance rule is shown in Figure 1.
Figure 1 — Symbol of the maximum tolerance acceptance rule
The maximum tolerance acceptance rule is the default case and valid with or without indication of the
‘Tmax’ symbol.
NOTE 1 The suffix ‘max’ can be interpreted as the required maximal conformity of the measured value.
NOTE 2 The ‘Tmax’ symbol can be used to prevent misinterpretation of a specification.
4.3 16 % tolerance acceptance rule
A specified 16 % tolerance acceptance rule allows at most 16 % of all measured values of a parameter to
violate the tolerance limit. The symbol of the 16 % tolerance acceptance rule is shown in Figure 2.
The 16 % tolerance acceptance rule shall be applied as specified in Annex E.
Figure 2 — Symbol of the 16 % tolerance acceptance rule
The 16 % tolerance acceptance rule is valid for the parameter on the line where the ‘T16 %’ symbol is
indicated.
If a bilateral tolerance is specified in one line, 16 % of all measured values may violate the upper
tolerance limit and 16 % of all measured values may violate the lower tolerance limit.
NOTE 1 The 16 % tolerance acceptance rule defines how tolerance limits are applied to the measured values.
NOTE 2 In ISO 1302, the 16 % tolerance acceptance rule was called the 16 % rule.
NOTE 3 In contrast to ISO 1302, the 16 % tolerance acceptance rule is not the default (see Annex F for
additional information).
NOTE 4 See ISO 21920-3:2021, Table 1 for the distribution of the measurements.
4.4 Median tolerance acceptance rule
If a median tolerance acceptance rule is specified, the median value of all measured values of a
parameter shall meet the tolerance limits. The symbol of the median tolerance acceptance rule is shown
in Figure 3.
Figure 3 — Symbol of the median tolerance acceptance rule
The median tolerance acceptance rule is valid for the parameter on the line where the ‘Tmed’ symbol is
indicated.
ISO 21920-1:2021(E)
At least three measured values shall be used to apply the median acceptance rule. A higher number of
measurements can be specified in “other requirements” (symbol OR(n), see 7.17).
NOTE 1 The median tolerance acceptance rule defines how tolerance limits are applied to the measured
values.
NOTE 2 If the median value of all measured values of a parameter meets the tolerance limit, no more than half
the measured values exceed the tolerance limit.
5 Specification elements for indication of profile surface texture specifications
5.1 General
Indications of profile surface texture specify requirements on the surface of a workpiece as well as the
specification operator.
NOTE All specification elements permitted for indication of profile surface texture specifications are listed
in 5.2 and 5.3 and described in Clause 7.
5.2 Mandatory indication to be explicitly specified
— Graphical symbol for profile surface tolerance.
— Symbol of the profile surface texture parameter.
— Tolerance limit of the profile surface texture parameter.
— For parameters without defined defaults: indication of the profile L-filter nesting index N for
ic
R-parameters or profile S-filter nesting index N for W-parameters or the setting class Scn.
ic
NOTE 1 Parameters without defined default are not listed in ISO 21920-3: 2021, Tables 3 to 6.
NOTE 2 The indication of the nesting index or the setting class is optional for all parameters listed in
ISO 21920-3:2021, Tables 3 to 6.
NOTE 3 It is the responsibility of the designer to choose and indicate the appropriate L-filter or S-filter.
ISO 21920-3:2021, Tables 3 to 6 define defaults that can be used for surfaces without particular performance
requirements.
NOTE 4 A cut-off wavelength for a profile filter is an example of a nesting index, see ISO 21920-2.
5.3 Optional indications to specify non-default or further requirements
— Tolerance type (upper, lower or bilateral tolerance limit).
— Symbol ‘T16 %’, ‘Tmax’ or ‘Tmed’ to specify a tolerance acceptance rule.
— Profile S-filter type.
— Profile S-filter nesting index.
— Profile L-filter type for R-parameters or profile S-filter type for W-parameters.
— Profile L-filter nesting index N for R-parameters or profile S-filter nesting index N for W-parameters.
ic ic
— Evaluation length l for the evaluation length parameters. Section length l and number of sections
e sc
n for the section length parameters.
sc
— Profile F-operator association method and element.
— Profile F-operator nesting index.
ISO 21920-1:2021(E)
— Method of profile extraction.
— Symbol ‘OR(n)’ to specify other requirements.
— Manufacturing process.
— Surface lay and direction of lay.
— Profile direction.
— Symbol ‘Scn’ to specify a setting class.
NOTE Default settings are defined in ISO 21920-3.
6 Indication of profile surface texture
6.1 General
Profile surface texture requirements in technical product specifications shall be specified by one of the
graphical symbols described in 6.2.
A minimal indication of profile surface texture shall be built up of the graphical symbol, the parameter
designation and the parameter tolerance limit value, see 6.3.
If several parameters are specified, the parameter in the first line is relevant for the determination of
default settings (see ISO 21920-3).
All indicated specification elements are separated by a single blank character.
NOTE 1 Exceptions are defined in 9.1.
NOTE 2 See Annex G, Table G.1, for new issues in this document and changes to previous documents.
6.2 Graphical symbols
The form of the graphical symbols contains requirements for the production process. Proportions of
the graphical symbols shall be indicated as specified in Annex A.
NOTE 1 See Figure 4 for the layout of the three defined graphical symbols and their interpretation.
NOTE 2 The bar above the symbol is to distinguish this symbol from the ones used in ISO 1302 and those used
for indication of areal surface texture specifications.
a) Any manufacturing process permitted
b) Material shall be removed
ISO 21920-1:2021(E)
c) Material removal is not permitted
Figure 4 — Graphical symbols indicating profile surface texture
6.3 Minimal indication
6.3.1 General
If a minimal indication is specified, all defaults shall be applied. Because defaults cannot be defined for
all parameters, the minimal indication is different for parameters with and without defined defaults.
6.3.2 Minimal indication for parameters with defined defaults
Figure 5 shows all symbols and indications mandatory for a minimal indication of profile surface
texture requirements and parameters with defined defaults.
Key
a symbol for parameter
b tolerance limit value of the profile surface texture parameter
< > placeholder has to be specified
Figure 5 — Minimal indication for parameter with defined defaults (all defaults apply)
NOTE 1 Parameters with defined defaults are Rz, Ra, Rp, Rv, Rq, Rmax, Rt and Pt, see ISO 21920-3:2021,
Tables 3 to 6.
NOTE 2 Exceptions are defined in 9.1.
NOTE 3 See Annex D for examples and additional information.
6.3.3 Minimal indication for parameters without defined defaults
Figure 6 shows all symbols and indications mandatory for a minimal indication of profile surface
texture requirements and parameters without defined defaults. All defaults are defined by the
mandatory specified setting class (Scn) or by one of the default values of the mandatory profile L-filter
nesting index N for R-parameters or profile S-filter nesting index N for W-parameters.
ic ic
Oblique strokes, “/”, are used to separate the specification sections.
ISO 21920-1:2021(E)
Key
a symbol for parameter
b tolerance limit value of the profile surface texture parameter
c symbol for the specified setting class Scn or a default value of profile L-filter nesting index N for R-parameters
ic
or profile S-filter nesting index N for W-parameters
ic
< > placeholder has to be specified
Figure 6 — Minimal indication for parameter without defined defaults
NOTE 1 Parameters without defined defaults are not listed in ISO 21920-3:2021, Tables 3 to 6.
NOTE 2 The specified setting class leads directly to the specified column of ISO 21920-3:2021, Table 2, with
the relevant default settings.
NOTE 3 Exceptions are defined in 9.1.
NOTE 4 See Annex D for examples and additional information.
6.4 Complete indication
6.4.1 General
The specification elements described in Clause 5 shall be arranged as shown in 6.4.2 to 6.4.5, depending
on the parameter type. All specification elements for one parameter shall be indicated in one line.
NOTE 1 If several parameters or different specification elements for the same parameter need to be specified,
the indication follows in one or several additional lines.
NOTE 2 See Annex D for examples of indication and additional information.
NOTE 3 The complete indication is shown to define the sequence of the indication of all specification elements
and might be rarely used in practice.
ISO 21920-1:2021(E)
6.4.2 Complete indication for evaluation length R-parameters
The specification elements for evaluation length R-parameters shall be arranged as shown in Figure 7.
NOTE Evaluation length R-parameters include Ra, Rq, Rt, Rzx and Rk (see ISO 21920-2).
Key
a tolerance type
b symbol for R-parameter
c tolerance limit value of the profile surface texture parameter
d tolerance acceptance rule
e profile S-filter type
f profile S-filter nesting index
g profile L-filter type
h profile L-filter nesting index
m evaluation length
n profile F-operator association method and element
p profile F-operator nesting index
q method of profile extraction
r placeholder for the OR(n) symbol for other requirements
s manufacturing process
t surface lay and direction of lay
u profile direction relative to the surface lay
< > placeholder has to be specified
[ ] placeholder can be specified if different from the default or an additional requirement
Figure 7 — Indication for evaluation length R-parameters including all optional specification
elements
ISO 21920-1:2021(E)
6.4.3 Complete indication for section length R-parameters
The specification elements for section length R-parameters shall be arranged as shown in Figure 8.
NOTE Section length R-parameters include Rz, Rp and Rv (see ISO 21920-2).
Key
a tolerance type
b symbol for R-parameter
c tolerance limit value of the profile surface texture parameter
d tolerance acceptance rule
e profile S-filter type
f profile S-filter nesting index
g profile L-filter type
h profile L-filter nesting index
i section length
k number of sections
n profile F-operator association method and element
p profile F-operator nesting index
q method of profile extraction
r placeholder for the OR(n) symbol for other requirements
s manufacturing process
t surface lay and direction of lay
u profile direction relative to the surface lay
< > placeholder has to be specified
[ ] placeholder can be specified if different from the default or an additional requirement
NOTE The parentheses around ([ i ] × [ k ]) bring out the relationship between these specification elements
as the evaluation length results from this product.
Figure 8 — Indication for section length R-parameters including all optional specification
elements
ISO 21920-1:2021(E)
6.4.4 Complete indication for evaluation length P-parameters and W-parameters
The specification elements for evaluation length P-parameters and W-parameters shall be arranged as
shown in Figure 9.
NOTE Evaluation length P-parameters and W-parameters include Pt, Pa, Wt and Wa (see ISO 21920-2).
Key
a tolerance type
b symbol for P-parameter or W-parameter
c tolerance limit value of the profile surface texture parameter
d tolerance acceptance rule
e profile S-filter type
f profile S-filter nesting index
m evaluation length
n profile F-operator association method and element
p profile F-operator nesting index
q method of profile extraction
r placeholder for the OR(n) symbol for other requirements
s manufacturing process
t surface lay and direction of lay
u profile direction relative to the surface lay
< > placeholder has to be specified
[ ] placeholder can be specified if different from the default
Figure 9 — Indication for evaluation length P-parameters and W-parameters including all
optional specification elements
ISO 21920-1:2021(E)
6.4.5 Complete indication for section length P-parameters and W-parameters
The specification elements for section length P-parameters and section length W-parameters shall be
arranged as shown in Figure 10.
NOTE Section length P-parameters and W-parameters include Pz, Pmax and Wz (see ISO 21920-2).
Key
a tolerance type
b symbol for P-parameter or W-parameter
c tolerance limit value of the profile surface texture parameter
d tolerance acceptance rule
e profile S-filter type
f profile S-filter nesting index
i section length
k number of sections
n profile F-operator association method and element
p profile F-operator nesting index
q method of profile extraction
r placeholder for the OR(n) symbol for other requirements
s manufacturing process
t surface lay and direction of lay
u profile direction relative to the surface lay
< > placeholder has to be specified
[ ] placeholder can be specified if different from the default
Figure 10 — Indication for section length P-parameters and W-parameters including all
optional specification elements
7 Rules for indication of profile surface texture specifications
7.1 General
The indication of profile surface texture specifications is arranged in a defined way to avoid ambiguities.
For all specification elements with variable values, defaults are defined which lead to reasonable and
repeatable results on uniform surfaces.
In case of a minimal indication and when the specified parameter is listed in ISO 21920-3:2021, Tables 3
to 6, the specified parameter with its tolerance type and limit are the basis for the default settings.
Otherwise, the specified profile filter nesting index value or the setting class is the basis for the default
settings.
NOTE 1 For all specification elements with variable values, default values are defined in ISO 21920-3.
NOTE 2 Values other than defaults can be useful for functional or practical reasons.
ISO 21920-1:2021(E)
NOTE 3 See 6.4 for the position of all specification elements.
7.2 Graphical symbol for the indication of profile surface texture specifications
When indicated, the graphical symbol indicates requirements to the surface of a workpiece.
NOTE See 6.2 for layout and interpretation of the graphical symbol.
7.3 Profile surface texture parameter
The parameter symbol shall always be indicated (exceptions are defined in 9.1) and includes two items
of information essential for the interpretation of the requirement:
— the first capital letter of the parameter symbol indicates which scale-limited profile (R, W or P) is
the basis for the calculation.
— the following letter(s) indicate(s) which parameter definition is used.
7.4 Tolerance limit value of the profile surface texture parameter
The tolerance limit value of the specified parameter shall always be indicated directly after the symbol
for the parameter separated by a single blank (exceptions are defined in 9.1).
7.5 Tolerance types
The profile surface texture requirement shall be indicated as a unilateral or bilateral tolerance. The
symbols are:
U for upper tolerance limit
L for lower tolerance limit
NOTE 1 The default tolerance type is upper tolerance limit (see ISO 21920-3).
NOTE 2 Bilateral tolerances are specified by a lower and an upper tolerance limit (for indication see 9.6).
7.6 Tolerance acceptance rule
The tolerance acceptance rule shall be indicated by ‘Tmax’ for the maximum tolerance acceptance rule,
‘T16 %’ for the 16 % tolerance acceptance rule or ‘Tmed’ for the median tolerance acceptance rule.
The maximum tolerance acceptance rule is the default case and valid with or without the indication of
‘Tmax’.
NOTE See Clause 4 for details.
7.7 Profile S-filter type
All profile filter types from the ISO 16610 series can be applied for the profile S-filter. The symbols for
profile filter types shall be indicated as specified in Annex B, Table B.1.
7.8 Profile S-filter nesting index
The profile S-filter nesting index value specifies which small-scale lateral components are removed (see
ISO 21920-2). The profile S-filter nesting index is specified in millimetres (mm).
NOTE 1 Profile S-filter nesting index N determines the maximum sampling distance for all profile surface
is
texture parameters (see ISO 21920-3:2021, Table 2).
NOTE 2 If the profile S-filter nesting index N is specified as zero, the scale-limitation is only determined by
is
the properties and internal settings of the instrument.
ISO 21920-1:2021(E)
7.9 Profile L-filter type (for R-parameter) or profile S-filter type (for W-parameter)
All profile filter types from the ISO 16610 series can be applied for the profile L-filter or the profile
S-filter. The symbo
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.
Loading comments...