EN ISO 21920-2:2022
(Main)Geometrical product specifications (GPS) - Surface texture: Profile - Part 2: Terms, definitions and surface texture parameters (ISO 21920-2:2021, Corrected version 2022-06)
Geometrical product specifications (GPS) - Surface texture: Profile - Part 2: Terms, definitions and surface texture parameters (ISO 21920-2:2021, Corrected version 2022-06)
This document specifies terms, definitions and parameters for the determination of surface texture by profile methods.
NOTE 1 The main changes to previous ISO profile documents are described in Annex I.
NOTE 2 An overview of profile and areal standards in the GPS matrix model is given in Annex J.
NOTE 3 The relation of this document to the GPS matrix model is given in Annex K.
Geometrische Produktspezifikation (GPS) - Oberflächenbeschaffenheit: Profile - Teil 2: Begriffe und Kenngrößen für die Oberflächenbeschaffenheit (ISO 21920 2:2021, korrigierte Fassung 2022-06)
Dieses Dokument legt Begriffe und Parameter für die Bestimmung der Oberflächenbeschaffenheit nach dem Tastschnittverfahren fest.
ANMERKUNG 1 Die wesentlichen Änderungen an früheren ISO-Profildokumenten werden in Anhang I beschrieben.
ANMERKUNG 2 Anhang J enthält einen Überblick über Normen zu profilhaften und flächenhaften Oberflächenbeschaffenheiten im GPS-Matrix-Modell.
ANMERKUNG 3 Anhang K enthält den Zusammenhang zwischen diesem Dokument und dem GPS-Matrix-Modell.
Spécification géométrique des produits (GPS) - État de surface: Méthode du profil - Partie 2: Termes, définitions et paramètres d'état de surface (ISO 21920-2:2021, Version corrigée 2022-06)
Le présent document spécifie les termes, définitions et paramètres applicables à la détermination de l’état de surface au moyen de méthodes de profil.
NOTE 1 Les principales modifications apportées aux précédents documents sur les profils ISO sont décrites à l'Annexe I.
NOTE 2 Une vue d'ensemble des normes de profil et des normes de surface dans le modèle matriciel GPS est donnée à l'Annexe J.
NOTE 3 La relation entre le présent document et le modèle de matrice GPS est donnée à l'Annexe K.
Specifikacija geometrijskih veličin izdelka (GPS) - Tekstura površine: profil - 2. del: Izrazi, definicije in parametri teksture površine (ISO 21920-2:2021, popravljena različica 2022-06)
Ta dokument določa izraze, definicije in parametre za ugotavljanje teksture površine s profilnimi metodami.
OPOMBA 1: Glavne spremembe prejšnjih dokumentov o profilu ISO so opisane v dodatku I.
OPOMBA 2: Pregled standardov o profilnih in ploskovnih metodah v matričnem modelu GPS je podan v dodatku J.
OPOMBA 3: Povezava tega dokumenta z matričnim modelom GPS je podana v dodatku K.
General Information
Relations
Overview
EN ISO 21920-2:2022 - Geometrical product specifications (GPS) - Surface texture: Profile - Part 2 - specifies the terms, definitions and surface texture parameters used when determining surface texture by profile methods. Adopted by CEN from ISO 21920-2:2021 (corrected 2022-06), this standard replaces several earlier profile standards and defines a consistent vocabulary and parameter set for profile-based surface texture measurement.
Key Topics
- Terms and definitions: A unified vocabulary for general, geometrical parameter and feature-related terms used in profile surface texture analysis.
- Field parameters: Categorized parameter types and their intent, including:
- Height parameters: arithmetic mean height, root mean square height, skewness, kurtosis, total height and maximum height per section.
- Spatial parameters: autocorrelation length, dominant spatial wavelength.
- Hybrid parameters: RMS gradient, mean absolute gradient, developed length and developed length ratio.
- Material ratio functions and parameters: material ratio curve, related parameters for stratified surfaces, and volume parameters.
- Feature parameters: Parameters based on peak/pit heights, profile element spacing and heights, peak count and feature characterization.
- Normative procedures and annexes: Guidance on derivatives, local curvature, material ratio curve determination, segmentation (crossing-the-line), feature characterization, and a specification analysis workflow.
- Relation to the GPS matrix: Overviews and mapping of profile and areal standards to the GPS matrix model (Annexes J and K).
- Supersession: Replaces EN ISO 12085, EN ISO 4287, EN ISO 13565-2 and -3.
Applications
EN ISO 21920-2:2022 is used by:
- Metrology and quality engineers writing surface finish specifications and inspection plans.
- Calibration and testing laboratories performing profile measurements and reporting surface texture parameters.
- Manufacturers (automotive, aerospace, tooling, bearings, seals) for process control, acceptance testing and verification of functional surface requirements.
- Standards bodies and technical committees aligning measurement vocabulary across areal and profile methods.
Practical uses include selecting appropriate profile parameters for functional performance assessment, defining measurement and reporting requirements, and ensuring consistent interpretation of surface texture results across suppliers and inspection labs.
Related standards
- EN ISO 21920-1 (GPS matrix and areal/profile context - see GPS matrix model)
- Superseded: EN ISO 12085, EN ISO 4287, EN ISO 13565-2 and EN ISO 13565-3
- Other GPS profile and areal standards referenced in the GPS matrix (see Annexes J and K)
For specification writers and practitioners, EN ISO 21920-2:2022 provides the authoritative vocabulary and parameter definitions needed to specify, measure and interpret profile surface texture consistently.
Frequently Asked Questions
EN ISO 21920-2:2022 is a standard published by the European Committee for Standardization (CEN). Its full title is "Geometrical product specifications (GPS) - Surface texture: Profile - Part 2: Terms, definitions and surface texture parameters (ISO 21920-2:2021, Corrected version 2022-06)". This standard covers: This document specifies terms, definitions and parameters for the determination of surface texture by profile methods. NOTE 1 The main changes to previous ISO profile documents are described in Annex I. NOTE 2 An overview of profile and areal standards in the GPS matrix model is given in Annex J. NOTE 3 The relation of this document to the GPS matrix model is given in Annex K.
This document specifies terms, definitions and parameters for the determination of surface texture by profile methods. NOTE 1 The main changes to previous ISO profile documents are described in Annex I. NOTE 2 An overview of profile and areal standards in the GPS matrix model is given in Annex J. NOTE 3 The relation of this document to the GPS matrix model is given in Annex K.
EN ISO 21920-2:2022 is classified under the following ICS (International Classification for Standards) categories: 01.040.17 - Metrology and measurement. Physical phenomena (Vocabularies); 17.040.40 - Geometrical Product Specification (GPS). The ICS classification helps identify the subject area and facilitates finding related standards.
EN ISO 21920-2:2022 has the following relationships with other standards: It is inter standard links to EN ISO 12085:1997, EN ISO 4287:1998, EN ISO 4287:1998/A1:2009, EN ISO 12085:1997/AC:2008, EN ISO 4287:1998/AC:2008, EN ISO 13565-2:1997, EN ISO 13565-3:2000. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
You can purchase EN ISO 21920-2:2022 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of CEN standards.
Standards Content (Sample)
SLOVENSKI STANDARD
01-marec-2022
Nadomešča:
SIST EN ISO 12085:2000
SIST EN ISO 12085:2000/AC:2008
SIST EN ISO 13565-2:2000
SIST EN ISO 13565-3:2002
SIST EN ISO 4287:2000
SIST EN ISO 4287:2000/A1:2011
SIST EN ISO 4287:2000/AC:2008
Specifikacija geometrijskih veličin izdelka (GPS) - Tekstura površine: profil - 2. del:
Izrazi, definicije in parametri teksture površine (ISO 21920-2:2021, popravljena
različica 2022-06)
Geometrical product specifications (GPS) - Surface texture: Profile - Part 2: Terms,
definitions and surface texture parameters (ISO 21920-2:2021, Corrected version 2022-
06)
Geometrische Produktspezifikation (GPS) - Oberflächenbeschaffenheit: Profile - Teil 2:
Begriffe und Parameter für die Oberflächenbeschaffenheit (ISO 21920-2:2021,
korrigierte Fassung 2022-06)
Ta slovenski standard je istoveten z: EN ISO 21920-2:2022
ICS:
01.040.17 Meroslovje in merjenje. Metrology and measurement.
Fizikalni pojavi (Slovarji) Physical phenomena
(Vocabularies)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 21920-2
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2022
EUROPÄISCHE NORM
ICS 01.040.17; 17.040.40 Supersedes EN ISO 12085:1997, EN ISO 13565-
2:1997, EN ISO 13565-3:2000, EN ISO 4287:1998
English Version
Geometrical product specifications (GPS) - Surface texture:
Profile - Part 2: Terms, definitions and surface texture
parameters (ISO 21920-2:2021, Corrected version 2022-06)
Spécification géométrique des produits (GPS) - État de Geometrische Produktspezifikation (GPS) -
surface: Méthode du profil - Partie 2: Termes, Oberflächenbeschaffenheit: Profile - Teil 2: Begriffe
définitions et paramètres d'état de surface (ISO 21920- und Parameter für die Oberflächenbeschaffenheit (ISO
2:2021, Version corrigée 2022-06) 21920-2:2021, korrigierte Fassung 2022-06)
This European Standard was approved by CEN on 27 November 2021.
This European Standard was corrected and reissued by the CEN-CENELEC Management Centre on 20 July 2022.
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, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATIO N
EUROPÄISCHES KOMITEE FÜR NORMUN G
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 21920-2:2022 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 21920-2:2022) 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 12085:1997, EN ISO 4287:1998, EN ISO 13565-2:1997 and
EN ISO 13565-3:2000.
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 21920-2:2021, Corrected version 2022-06 has been approved by CEN as EN ISO 21920-
2:2022 without any modification.
INTERNATIONAL ISO
STANDARD 21920-2
First edition
2021-12
Corrected version
2022-06
Geometrical product specifications
(GPS) — Surface texture: Profile —
Part 2:
Terms, definitions and surface texture
parameters
Spécification géométrique des produits (GPS) — État de surface:
Méthode du profil —
Partie 2: Termes, définitions et paramètres d’état de surface
Reference number
ISO 21920-2:2021(E)
ISO 21920-2:2021(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 21920-2:2021(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 General terms . 1
3.2 Geometrical parameter terms . 10
3.3 Geometrical feature terms . . 14
4 Field parameters .22
4.1 General .22
4.2 Height parameters. 22
4.2.1 General .22
4.2.2 Arithmetic mean height .22
4.2.3 Root mean square height . 22
4.2.4 Skewness . 22
4.2.5 Kurtosis .22
4.2.6 Total height .23
4.2.7 Maximum height per section . 23
4.3 Spatial parameters . 24
4.3.1 General . 24
4.3.2 Autocorrelation length. 24
4.3.3 Dominant spatial wavelength . 24
4.4 Hybrid parameters . . . 25
4.4.1 General . 25
4.4.2 Root mean square gradient . 25
4.4.3 Arithmetic mean of absolute gradient . 25
4.4.4 Maximum absolute gradient . 25
4.4.5 Developed length . 25
4.4.6 Developed length ratio .26
4.5 Material ratio functions and related parameters . 26
4.5.1 Material ratio functions .26
4.5.2 Material ratio parameters. 31
4.5.3 Parameters for stratified surfaces using the material ratio curve .33
4.5.4 Parameters for stratified surfaces using the material probability curve . 35
4.5.5 Volume parameters .36
5 Feature parameters .38
5.1 Parameters based on peak heights and pit depths .38
5.1.1 General .38
5.1.2 Maximum peak height . 39
5.1.3 Mean peak height . 39
5.1.4 Maximum pit depth . 39
5.1.5 Mean pit depth .40
5.1.6 Maximum height .40
5.2 Parameters based on profile elements .40
5.2.1 General .40
5.2.2 Mean profile element spacing . 42
5.2.3 Maximum profile element spacing . 42
5.2.4 Standard deviation of profile element spacings . 42
5.2.5 Mean profile element height . 42
5.2.6 Maximum profile element height . 42
5.2.7 Standard deviation of profile element heights . 42
5.2.8 Peak count parameter . 43
iii
ISO 21920-2:2021(E)
5.3 Parameters based on feature characterization. 43
5.3.1 General . 43
5.3.2 Named feature parameters . 43
Annex A (informative) Determination of the first and second derivative .45
Annex B (informative) Determination of the local curvature .48
Annex C (normative) Determination of the material ratio curve .49
Annex D (normative) Determination of profile parameters for stratified surfaces .50
Annex E (normative) Crossing-the-line segmentation to determine profile elements .59
Annex F (normative) Feature characterization .65
Annex G (informative) Summary of profile surface texture parameters and functions .69
Annex H (informative) Specification analysis workflow .72
Annex I (informative) Changes to previous ISO profile documents .74
Annex J (informative) Overview of profile and areal standards in the GPS matrix model .75
Annex K (informative) Relation to the GPS matrix model .76
Bibliography .77
iv
ISO 21920-2:2021(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 first edition of ISO 21920-2 cancels and replaces ISO 4287:1997, ISO 13565-2:1996 and
ISO 13565-3:1998, which have been technically revised.
It also incorporates the Amendment ISO 4287:1997/Amd 1:2009 and the Technical Corrigenda
ISO 4287:1997/Cor 1:1998, ISO 4287:1997/Cor 2:2005 and ISO 13565-2:1996/Cor 1:1998.
The main changes are related to ISO 4287 and are as follows:
— all field parameters are now related to the evaluation length;
— unambiguous evaluation of profile elements;
— definition of new parameters, in particular parameters based on the watershed transformation.
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.
This corrected version of ISO 21920-2:2021 incorporates the following corrections:
— ISO 12085:1996 and ISO 12085:1996/Cor 1:1998 have been removed from the list of documents
which this document replaces as they have been reinstated.
v
ISO 21920-2:2021(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 B 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 K.
This document develops the terminology, concepts and parameters for profile surface texture.
Throughout this document, parameters are written as abbreviated terms with lower-case suffixes (as
in Rq) when used in a sentence, and are written as symbols with subscripts (as in R ) when used in
q
formulae, to avoid misinterpretations of compound letters as an indication of multiplication between
quantities in formulae. The parameters with lower-case suffixes are used in product documentation,
drawings and data sheets.
vi
INTERNATIONAL STANDARD ISO 21920-2:2021(E)
Geometrical product specifications (GPS) — Surface
texture: Profile —
Part 2:
Terms, definitions and surface texture parameters
1 Scope
This document specifies terms, definitions and parameters for the determination of surface texture by
profile methods.
NOTE 1 The main changes to previous ISO profile documents are described in Annex I.
NOTE 2 An overview of profile and areal standards in the GPS matrix model is given in Annex J.
NOTE 3 The relation of this document to the GPS matrix model is given in Annex K.
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 16610-1:2015, Geometrical product specifications (GPS) — Filtration — Part 1: Overview and basic
concepts
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 16610-1 and the following
apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1 General terms
3.1.1
skin model
non-ideal surface model
model of the physical interface of the workpiece with its environment
[SOURCE: ISO 17450-1:2011, 3.2.2]
3.1.2
surface texture
geometrical irregularities contained in a scale-limited profile
Note 1 to entry: Surface texture does not include geometrical irregularities contributing to the form or shape of
the profile.
ISO 21920-2:2021(E)
3.1.3
mechanical surface
boundary of the mathematical erosion, by a sphere of radius r , of the locus of the centre of an ideal
tactile sphere, also with radius r , rolled over the skin model of a workpiece
Note 1 to entry: Figure 1 is an example to show the effect of mechanical filtering and is not related to a real
measured surface.
[SOURCE: ISO 14406:2010, 3.1.1, modified — Notes to entry replaced.]
Key
A skin model
B
ideal tactile sphere of radius r
C envelope curve of the locus of the centre of an ideal tactile sphere B rolled over the skin model
D sphere of radius r
E mechanical surface: boundary of the mathematical erosion, by the sphere D, of the envelope curve C
Figure 1 — Mechanical surface
ISO 21920-2:2021(E)
3.1.4
profile trace
intersection of the skin model by an intersection plane perpendicular to the skin model and in a
specified direction
Note 1 to entry: See Figure 2.
Note 2 to entry: See ISO 21920-3:2021, 4.3.
Key
A skin model
B intersection plane
C profile trace
Figure 2 — Profile trace
3.1.5
mechanical profile
boundary of the mathematical erosion, by a circular disc of radius r, of the locus of the centre of an ideal
tactile sphere, also with radius r, rolled along a trace over the skin model of a workpiece
Note 1 to entry: Figure 3 is an example to show the effect of mechanical filtering and is not related to a real
measured profile.
Note 2 to entry: The treatment of non-measured points and spurious points is part of the extraction process (see
ISO 17450-1:2011, 8.1.3) and is not considered in this document.
ISO 21920-2:2021(E)
Key
A skin model
B
ideal tactile sphere of radius r
C envelope curve of the planar locus of the centre of an ideal tactile sphere rolled over the skin model
D
circular disc of radius r
E mechanical profile: boundary of the mathematical erosion, by the circular disc D, of the envelope curve C
Figure 3 — Mechanical profile
3.1.6
electromagnetic surface
surface obtained by the electromagnetic interaction with the skin model of a workpiece
Note 1 to entry: See Figure 4.
Note 2 to entry: The electromagnetic surface is an inherent characteristic of a skin model of a workpiece.
Note 3 to entry: Electromagnetic surfaces depend on the optical measurement principle used for extraction.
[SOURCE: ISO 14406:2010, 3.1.2, modified — Notes to entry replaced.]
ISO 21920-2:2021(E)
Figure 4 — Electromagnetic surface
3.1.7
electromagnetic profile
profile obtained by the electromagnetic interaction with the skin model of a workpiece
Note 1 to entry: See Figure 5.
Note 2 to entry: The electromagnetic profile is an inherent characteristic of a skin model of a workpiece.
Note 3 to entry: Electromagnetic profiles depend on the optical measurement principle used for extraction.
Note 4 to entry: In most cases, the profile trace results from the intersection of the skin model by an intersection
plane perpendicular to the skin model (3.1.1) and in a specified direction (see ISO 21920-3).
Note 5 to entry: The treatment of non-measured points and spurious points is part of the extraction process and
is not considered in this document.
Figure 5 — Electromagnetic profile
3.1.8
auxiliary surface
surface obtained by an interaction, other than mechanical or electromagnetic, with the skin model
(3.1.1) of a workpiece
Note 1 to entry: A software measurement standard is an example of an auxiliary surface. Other physical
measurement principles which differ from a mechanical or electromagnetic surface, such as scanning tunnelling
microscopy or atomic force microscopy, can also serve as an auxiliary surface. See Figure 6.
3.1.9
auxiliary profile
profile obtained by an interaction, other than mechanical or electromagnetic, with the skin model (3.1.1)
of a workpiece
Note 1 to entry: A software measurement standard is an example of an auxiliary profile. Other physical
measurement principles which differ from a mechanical or electromagnetic profile, such as scanning tunnelling
microscopy or atomic force microscopy, can also serve as an auxiliary profile. See Figure 6 and Annex H.
3.1.10
specification coordinate system
system of coordinates in which surface texture parameters are specified
Note 1 to entry: If the nominal surface is a plane (or portion of a plane), it is common practice to use a rectangular
coordinate system in which the axes form a right-handed Cartesian set, the x -axis and the y -axis also lying on
the nominal surface, and the z -axis being in an outward direction (from the material to the surrounding
medium). This convention is adopted throughout the rest of this document.
ISO 21920-2:2021(E)
3.1.11
nesting index
N , N , N
is ic if
number or set of numbers indicating the relative level of nesting for a particular primary mathematical
model
Note 1 to entry: The cut-off wavelength for the Gaussian filter is an example of a nesting index.
Note 2 to entry: Using the different nesting indices, specific lateral scale components of a scale-limited profile are
extracted.
[SOURCE: ISO 16610-1:2015, 3.2.1, modified — definition and notes to entry revised.]
3.1.12
primary surface profile
surface profile trace obtained when a surface profile trace is represented as a specified primary
mathematical model with specified nesting index N
is
Note 1 to entry: In the ISO 21920 series, a profile S-filter is used to derive the primary surface profile from a
profile trace (e.g. mechanical profile). See Figure 6 and Annex H.
Note 2 to entry: For some applications, the profile S-filter is not used. In such cases, for example for multi-scale
analysis, the nesting index is equal to “zero”.
Note 3 to entry: In most situations, the primary surface profile can be derived with sufficient accuracy from
either the mechanical surface (the default choice), the electromagnetic surface or the auxiliary surface, using an
intersection plane perpendicular to the chosen type of surface and in a specified direction. See Figure 6.
NOTE The evaluation chain for the default case is indicated by the grey fill colour.
a
See 3.1.13.1 for profile S-filter.
b
See ISO 25178-2:2021, 3.1.6.1, for S-filter.
c
See ISO 25178-2:2021, 3.1.5, for primary surface.
Figure 6 — Definition of the primary surface and primary surface profile
3.1.13
profile filter
filtration operator applied to a profile
ISO 21920-2:2021(E)
3.1.13.1
profile S-filter
profile filter which removes small lateral scale components from a profile
Note 1 to entry: See Figure 7.
3.1.13.2
profile L-filter
profile filter which removes large lateral scale components from a profile
Note 1 to entry: Some profile L-filters are sensitive to form and require the profile F-operation first as a prefilter
before being applied.
Note 2 to entry: See Figure 7.
3.1.13.3
profile F-operation
operation which removes form from a profile
Note 1 to entry: See Figure 7.
Key
A small lateral scale (e.g. short wavelengths)
B large lateral scale (e.g. long wavelengths)
C scale axis
D amplitude axis
E lateral scale component extracted by the profile S-filter
F lateral scale component extracted by the profile F-operation
G lateral scale component extracted by the profile L-filter
H profile S-filter nesting index N
is
I profile F-operation nesting index N
if
J profile L-filter nesting index N
ic
Figure 7 — Relationships between the S-filter, L-filter and F-operation
ISO 21920-2:2021(E)
3.1.14
scale-limited profile
profile structure scale components between specified nesting indices
EXAMPLE A profile is scale-limited after applying a profile filter with a specified nesting index.
3.1.14.1
primary profile
P-profile
scale-limited profile at any position x derived from the primary surface profile by removing the form
using a profile F-operation with nesting index N
if
Note 1 to entry: In most cases, the primary profile can be derived with sufficient accuracy from the S-F surface
using an intersection plane perpendicular to the S-F surface and in a specified direction. See Figure 8.
Note 2 to entry: The primary profile is the basis for evaluation of the P-parameters (3.2.5). See Figures 9 and 10.
Note 3 to entry: The profile F-operation can be performed as a multi-stage operation, for example a combination
of a total least square fit and a profile L-filter.
Note 4 to entry: See Annex H for additional information.
NOTE The evaluation chain for the default case is indicated by the grey fill colour.
a
See ISO 25178-2:2021, 3.1.6.3, for F-operation.
b
See ISO 25178-2:2021, 3.1.7, for S-F surface.
Figure 8 — Primary profile derived from the primary surface profile (default) or S-F surface
3.1.14.2
waviness profile
W-profile
scale-limited profile at any position x derived from the primary profile by removing small-scale lateral
components by a specific type of profile S-filter with a nesting index N
ic
Note 1 to entry: The waviness profile is the basis for evaluation of the W-parameters (3.2.6). See Figures 9 and 10.
Note 2 to entry: The choice of filter settings for W-parameters is highly dependent on the functional requirements.
This is why no default tables for W-parameters are found in ISO 21920-3.
Note 3 to entry: See Annex H for additional information.
ISO 21920-2:2021(E)
3.1.14.3
roughness profile
R-profile
scale-limited profile at any position x derived from the primary profile by removing large-scale lateral
components by a specific type of profile L-filter with a nesting index N
ic
Note 1 to entry: The roughness profile is the basis for evaluation of the R-parameters (3.2.7). See Figures 9 and
10.
Note 2 to entry: See Annex H for additional information.
Key
A small lateral scale
B large lateral scale
C scale axis
D amplitude axis
E lateral scale component of primary surface profile
F lateral scale component of P-profile
G lateral scale component of W-profile
H lateral scale component of R-profile
I profile S-filter nesting index N
is
J profile F-operation nesting index N
if
K profile L-filter nesting index N
ic
Figure 9 — Relationship between the primary surface profile, P-profile, W-profile and R-profile
ISO 21920-2:2021(E)
Figure 10 — Measuring chain to determine the P-profile, W-profile and R-profile
3.1.15
reference line
line corresponding to a specific large lateral scale component
Note 1 to entry: The x -axis of the specification coordinate system (3.1.10) coincides with the reference line of the
assessed profile and the z -axis is oriented in an outward direction (from the material to the surrounding
medium). This convention is adopted throughout the rest of this document.
Note 2 to entry: The reference line for the primary profile and waviness profile are the large lateral scale
component of primary surface profile removed by the profile F-operation.
Note 3 to entry: The reference line for the roughness profile is the component of the primary profile removed by
the profile L-filter.
3.1.16
evaluation length
l
e
length in the direction of the x -axis used for identifying the geometrical structures characterizing the
scale-limited profile
Note 1 to entry: The traverse length is longer than the evaluation length.
Note 2 to entry: See 3.2.3 for evaluation length parameters.
Note 3 to entry: In ISO 4287, the evaluation length was given by l .
n
3.1.17
section length
l
sc
length in the direction of the x -axis used to obtain section length parameters (3.2.4)
Note 1 to entry: Default values of l are found in ISO 21920-3.
sc
3.1.18
number of sections
n
sc
integer number used to obtain section length parameters (3.2.4)
Note 1 to entry: Default values of n are found in ISO 21920-3.
sc
3.2 Geometrical parameter terms
ISO 21920-2:2021(E)
NOTE Parameter symbols are written with subscripts (e.g. R ) when used in formulae to avoid
q
misinterpretations of compound letters as an indication of multiplication between quantities. Parameter symbols
are written with lower-case suffixes (e.g. Rq ) when used in product documentation, drawings and data sheets.
3.2.1
field parameter
parameter defined from all the points on a scale-limited profile
3.2.2
feature parameter
parameter defined from a subset of predefined topographic features from the scale-limited profile
Note 1 to entry: For feature parameters, see Clause 5.
3.2.3
evaluation length parameter
parameter defined on the evaluation length
Note 1 to entry: See Clause 4, 5.2 and 5.3 for evaluation length parameters.
3.2.4
section length parameter
parameter defined on a set of section length
Note 1 to entry: See 5.1 for section length parameters.
3.2.5
P-parameter
parameter determined from the primary profile
3.2.6
W-parameter
parameter determined from the waviness profile
3.2.7
R-parameter
parameter determined from the roughness profile
Note 1 to entry: Formulae for parameter definitions are exemplarily given for R-parameters. P- and W-parameters
are defined in a similar manner, replacing the parameters related to the R-profile with those related to the
P-profile or W-profile. Default specification operators for the different types of parameter definitions can be
found in ISO 21920-3.
3.2.8
height
signed normal distance from the reference line to the scale-limited profile
Note 1 to entry: Where the scale-limited profile is below the reference line, the height has a negative value.
Note 2 to entry: This definition as an absolute coordinate applies when the term ‘height’ is used alone. Later
terms in this document include the word ‘height’ or ‘depth’ in their name, such as the maximum height Rz (see
5.1.6) or dale local depth (3.3.18). The definitions of some of those later terms use an alternative reference point
and/or refer to an unsigned distance in a specified direction from the reference point. See those definitions for
details.
3.2.9
depth
height multiplied by minus one
Note 1 to entry: Where the scale-limited profile is above the reference line, the depth has a negative value.
ISO 21920-2:2021(E)
Note 2 to entry: This definition as an absolute coordinate applies when the term ‘depth’ is used alone. Later terms
in this document include the word ‘height’ or ‘depth’ in their name, such as the maximum height Rz (see 5.1.6) or
dale local depth (3.3.18). The definitions of some of those later terms use an alternative reference point and/or
refer to an unsigned distance in a specified direction from the reference point. See those definitions for details.
3.2.10
ordinate value
zx()
height of the assessed scale-limited profile
3.2.11
local gradient
ddzx()/ x
first derivative of the scale-limited profile z with respect to the position x
Note 1 to entry: See Annex A for the determination of the gradient.
Note 2 to entry: The local gradient is also called slope.
3.2.12
local curvature
κ x
()
curvature of the scale-limited profile z with respect to the position x
ddzx() x
κ()x = (1)
1+ ddzx x
()()
()
Note 1 to entry: See Annex A and Annex B for the determination of the curvature.
Note 2 to entry: For most engineering surfaces, the local gradient (slope) is small, enabling a good approximation
of local curvature by the local second derivative κ()xz≅ dd()xx/ .
() ()
3.2.13
autocorrelation function
ft
()
ACFx
function which describes the correlation between a scale-limited profile z and the same profile spatial
shifted by t
x
zx −zz xt+ −zxd
()() ()()
x
∫
lt−
ex
l
ft()= (2)
ACFx
l
e
()zx()−zxd
∫
l
e
where
z is the arithmetic mean of the profile zx() over the evaluation length l ;
e
lx=∈{}R | mmax,()0 −tx≤≤ in()ll, −t is the overlap interval;
0 xe ex
tl< is the spatial shift.
xe
Note 1 to entry: See Figure 11 for an illustration of the overlap interval.
Note 2 to entry: The autocorrelation function is symmetrical in t , i.e. ft =−ft .
() ()
x ACFx ACFx
Note 3 to entry: Formula (2) is an unbiased estimator for the autocorrelation function.
ISO 21920-2:2021(E)
Note 4 to entry: Some disciplines use a shift-dependent Pearson correlation coefficient instead of the
autocorrelation function. It is defined by Formula (3).
zx −zz xt+ −zxd
()() ()()
x
∫
l
ρ ()t = with −≤11ρ ()t ≤ (3)
XX x XX x
2 22
()zx()−zxd ⋅+()zx()tz− dx
x
∫ ∫
l l
0 0
Key
A height C
overlap interval l
B
x -axis (reference line)
Figure 11 — Illustration of the overlap interval l
3.2.14
Fourier transformation
Fp
()
operator which transforms the scale-limited profile z into Fourier domain
l
e
−i2πpx
Fp()= zx() exd (4)
∫
where
i is the imaginary unit i =−1 ;
p
is the spatial frequency.
3.2.15
amplitude spectral density
fp()
ASD
absolute value of the Fourier transformation of the scale-limited profile z
fp = Fp (5)
() ()
ASD
where
is the Fourier transformation of the scale-limited profile z ;
Fp
()
p
is the spatial frequency.
ISO 21920-2:2021(E)
3.2.16
power spectral density
fp
()
PSD
function which describes the power of a scale-limited profile z in the Fourier domain
Fp()
fp()= (6)
PSD
l
e
where
is the Fourier transformation of the scale-limited profile z ;
Fp()
p
is the spatial frequency.
Note 1 to entry: The power spectral density fulfils Formula (7):
l
∞
e
zx()ddxf= ()pp (7)
PSD
∫∫
l
e
0 −∞
3.3 Geometrical feature terms
3.3.1
segmentation
method which partitions a scale-limited profile into distinct features
Note 1 to entry: There are three types of segmentation:
— for the parameters based on peak heights and pit depths (see 5.1), the segmentation is realized by identification
of the hills (3.3.11) and dales (3.3.17) by determination of the positions where the ordinate values change
their sign or are equal
...
SLOVENSKI STANDARD
01-marec-2022
Nadomešča:
SIST EN ISO 12085:2000
SIST EN ISO 12085:2000/AC:2008
SIST EN ISO 13565-2:2000
SIST EN ISO 13565-3:2002
SIST EN ISO 4287:2000
SIST EN ISO 4287:2000/A1:2011
SIST EN ISO 4287:2000/AC:2008
Specifikacija geometrijskih veličin izdelka (GPS) - Tekstura površine: profil - 2. del:
Izrazi, definicije in parametri teksture površine (ISO 21920-2:2021)
Geometrical product specifications (GPS) - Surface texture: Profile - Part 2: Terms,
definitions and surface texture parameters (ISO 21920-2:2021)
Geometrische Produktspezifikation (GPS) - Oberflächenbeschaffenheit: Profile - Teil 2:
Begriffe und Parameter für die Oberflächenbeschaffenheit (ISO 21920-2:2021)
Spécification géométrique des produits (GPS) - État de surface: Méthode du profil -
Partie 2: Termes, définitions et paramètres d'état de surface (ISO 21920-2:2021)
Ta slovenski standard je istoveten z: EN ISO 21920-2:2022
ICS:
01.040.17 Meroslovje in merjenje. Metrology and measurement.
Fizikalni pojavi (Slovarji) Physical phenomena
(Vocabularies)
17.040.20 Lastnosti površin Properties of surfaces
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 21920-2
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2022
EUROPÄISCHE NORM
ICS 01.040.17; 17.040.40 Supersedes EN ISO 12085:1997, EN ISO 4287:1998,
EN ISO 13565-2:1997, EN ISO 13565-3:2000, EN ISO
4287:1998/A1:2009, EN ISO 4287:1998/AC:2008, EN
ISO 12085:1997/AC:2008
English Version
Geometrical product specifications (GPS) - Surface texture:
Profile - Part 2: Terms, definitions and surface texture
parameters (ISO 21920-2:2021)
Spécification géométrique des produits (GPS) - État de Geometrische Produktspezifikation (GPS) -
surface: Méthode du profil - Partie 2: Termes, Oberflächenbeschaffenheit: Profile - Teil 2: Begriffe
définitions et paramètres d'état de surface (ISO 21920- und Parameter für die Oberflächenbeschaffenheit (ISO
2:2021) 21920-2:2021)
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 21920-2:2022 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 21920-2:2022) 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 12085:1997, EN ISO 4287:1998, EN ISO 13565-2:1997 and
EN ISO 13565-3:2000.
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 21920-2:2021 has been approved by CEN as EN ISO 21920-2:2022 without any
modification.
INTERNATIONAL ISO
STANDARD 21920-2
First edition
2021-12
Geometrical product specifications
(GPS) — Surface texture: Profile —
Part 2:
Terms, definitions and surface texture
parameters
Spécification géométrique des produits (GPS) — État de surface:
Méthode du profil —
Partie 2: Termes, définitions et paramètres d’état de surface
Reference number
ISO 21920-2:2021(E)
ISO 21920-2:2021(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 21920-2:2021(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 General terms . 1
3.2 Geometrical parameter terms . 10
3.3 Geometrical feature terms . . 14
4 Field parameters .22
4.1 General .22
4.2 Height parameters. 22
4.2.1 General .22
4.2.2 Arithmetic mean height .22
4.2.3 Root mean square height . 22
4.2.4 Skewness . 22
4.2.5 Kurtosis . 22
4.2.6 Total height . 23
4.2.7 Maximum height per section . 23
4.3 Spatial parameters . 24
4.3.1 General . 24
4.3.2 Autocorrelation length. 24
4.3.3 Dominant spatial wavelength . 24
4.4 Hybrid parameters . . . 25
4.4.1 General . 25
4.4.2 Root mean square gradient . 25
4.4.3 Arithmetic mean of absolute gradient . 25
4.4.4 Maximum absolute gradient . 25
4.4.5 Developed length . 25
4.4.6 Developed length ratio .26
4.5 Material ratio functions and related parameters . 26
4.5.1 Material ratio functions .26
4.5.2 Material ratio parameters. 31
4.5.3 Parameters for stratified surfaces using the material ratio curve .33
4.5.4 Parameters for stratified surfaces using the material probability curve .35
4.5.5 Volume parameters .36
5 Feature parameters .38
5.1 Parameters based on peak heights and pit depths .38
5.1.1 General .38
5.1.2 Maximum peak height .39
5.1.3 Mean peak height . 39
5.1.4 Maximum pit depth .39
5.1.5 Mean pit depth .40
5.1.6 Maximum height .40
5.2 Parameters based on profile elements .40
5.2.1 General .40
5.2.2 Mean profile element spacing . 42
5.2.3 Maximum profile element spacing . 42
5.2.4 Standard deviation of profile element spacings . 42
5.2.5 Mean profile element height . 42
5.2.6 Maximum profile element height . 42
5.2.7 Standard deviation of profile element heights . 42
5.2.8 Peak count parameter . 43
iii
ISO 21920-2:2021(E)
5.3 Parameters based on feature characterization. 43
5.3.1 General . 43
5.3.2 Named feature parameters . 43
Annex A (informative) Determination of the first and second derivative .45
Annex B (informative) Determination of the local curvature .48
Annex C (normative) Determination of the material ratio curve .49
Annex D (normative) Determination of profile parameters for stratified surfaces .50
Annex E (normative) Crossing-the-line segmentation to determine profile elements .59
Annex F (normative) Feature characterization .65
Annex G (informative) Summary of profile surface texture parameters and functions .69
Annex H (informative) Specification analysis workflow .72
Annex I (informative) Changes to previous ISO profile documents .74
Annex J (informative) Overview of profile and areal standards in the GPS matrix model .75
Annex K (informative) Relation to the GPS matrix model .76
Bibliography .77
iv
ISO 21920-2:2021(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 first edition of ISO 21920-2 cancels and replaces ISO 4287:1997, ISO 12085:1996, ISO 13565-2:1996
and ISO 13565-3:1998, which have been technically revised.
It also incorporates the Amendment ISO 4287:1997/Amd 1:2009 and the Technical Corrigenda
ISO 4287:1997/Cor 1:1998, ISO 4287:1997/Cor 2:2005, ISO 12085:1996/Cor 1:1998 and
ISO 13565-2:1996/Cor 1:1998.
The main changes are related to ISO 4287 and are as follows:
— all field parameters are now related to the evaluation length;
— unambiguous evaluation of profile elements;
— definition of new parameters, in particular parameters based on the watershed transformation.
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 21920-2:2021(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 B 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 K.
This document develops the terminology, concepts and parameters for profile surface texture.
Throughout this document, parameters are written as abbreviated terms with lower-case suffixes (as
in Rq) when used in a sentence, and are written as symbols with subscripts (as in R ) when used in
q
formulae, to avoid misinterpretations of compound letters as an indication of multiplication between
quantities in formulae. The parameters with lower-case suffixes are used in product documentation,
drawings and data sheets.
vi
INTERNATIONAL STANDARD ISO 21920-2:2021(E)
Geometrical product specifications (GPS) — Surface
texture: Profile —
Part 2:
Terms, definitions and surface texture parameters
1 Scope
This document specifies terms, definitions and parameters for the determination of surface texture by
profile methods.
NOTE 1 The main changes to previous ISO profile documents are described in Annex I.
NOTE 2 An overview of profile and areal standards in the GPS matrix model is given in Annex J.
NOTE 3 The relation of this document to the GPS matrix model is given in Annex K.
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 16610-1:2015, Geometrical product specifications (GPS) — Filtration — Part 1: Overview and basic
concepts
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 16610-1 and the following
apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1 General terms
3.1.1
skin model
non-ideal surface model
model of the physical interface of the workpiece with its environment
[SOURCE: ISO 17450-1:2011, 3.2.2]
3.1.2
surface texture
geometrical irregularities contained in a scale-limited profile
Note 1 to entry: Surface texture does not include geometrical irregularities contributing to the form or shape of
the profile.
ISO 21920-2:2021(E)
3.1.3
mechanical surface
boundary of the mathematical erosion, by a sphere of radius r , of the locus of the centre of an ideal
tactile sphere, also with radius r , rolled over the skin model of a workpiece
Note 1 to entry: Figure 1 is an example to show the effect of mechanical filtering and is not related to a real
measured surface.
[SOURCE: ISO 14406:2010, 3.1.1, modified — Notes to entry replaced.]
Key
A skin model
B
ideal tactile sphere of radius r
C envelope curve of the locus of the centre of an ideal tactile sphere B rolled over the skin model
D sphere of radius r
E mechanical surface: boundary of the mathematical erosion, by the sphere D, of the envelope curve C
Figure 1 — Mechanical surface
ISO 21920-2:2021(E)
3.1.4
profile trace
intersection of the skin model by an intersection plane perpendicular to the skin model and in a
specified direction
Note 1 to entry: See Figure 2.
Note 2 to entry: See ISO 21920-3:2021, 4.3.
Key
A skin model
B intersection plane
C profile trace
Figure 2 — Profile trace
3.1.5
mechanical profile
boundary of the mathematical erosion, by a circular disc of radius r, of the locus of the centre of an ideal
tactile sphere, also with radius r, rolled along a trace over the skin model of a workpiece
Note 1 to entry: Figure 3 is an example to show the effect of mechanical filtering and is not related to a real
measured profile.
Note 2 to entry: The treatment of non-measured points and spurious points is part of the extraction process (see
ISO 17450-1:2011, 8.1.3) and is not considered in this document.
ISO 21920-2:2021(E)
Key
A skin model
B
ideal tactile sphere of radius r
C envelope curve of the planar locus of the centre of an ideal tactile sphere rolled over the skin model
D
circular disc of radius r
E mechanical profile: boundary of the mathematical erosion, by the circular disc D, of the envelope curve C
Figure 3 — Mechanical profile
3.1.6
electromagnetic surface
surface obtained by the electromagnetic interaction with the skin model of a workpiece
Note 1 to entry: See Figure 4.
Note 2 to entry: The electromagnetic surface is an inherent characteristic of a skin model of a workpiece.
Note 3 to entry: Electromagnetic surfaces depend on the optical measurement principle used for extraction.
[SOURCE: ISO 14406:2010, 3.1.2, modified — Notes to entry replaced.]
ISO 21920-2:2021(E)
Figure 4 — Electromagnetic surface
3.1.7
electromagnetic profile
profile obtained by the electromagnetic interaction with the skin model of a workpiece
Note 1 to entry: See Figure 5.
Note 2 to entry: The electromagnetic profile is an inherent characteristic of a skin model of a workpiece.
Note 3 to entry: Electromagnetic profiles depend on the optical measurement principle used for extraction.
Note 4 to entry: In most cases, the profile trace results from the intersection of the skin model by an intersection
plane perpendicular to the skin model (3.1.1) and in a specified direction (see ISO 21920-3).
Note 5 to entry: The treatment of non-measured points and spurious points is part of the extraction process and
is not considered in this document.
Figure 5 — Electromagnetic profile
3.1.8
auxiliary surface
surface obtained by an interaction, other than mechanical or electromagnetic, with the skin model
(3.1.1) of a workpiece
Note 1 to entry: A software measurement standard is an example of an auxiliary surface. Other physical
measurement principles which differ from a mechanical or electromagnetic surface, such as scanning tunnelling
microscopy or atomic force microscopy, can also serve as an auxiliary surface. See Figure 6.
3.1.9
auxiliary profile
profile obtained by an interaction, other than mechanical or electromagnetic, with the skin model (3.1.1)
of a workpiece
Note 1 to entry: A software measurement standard is an example of an auxiliary profile. Other physical
measurement principles which differ from a mechanical or electromagnetic profile, such as scanning tunnelling
microscopy or atomic force microscopy, can also serve as an auxiliary profile. See Figure 6 and Annex H.
3.1.10
specification coordinate system
system of coordinates in which surface texture parameters are specified
Note 1 to entry: If the nominal surface is a plane (or portion of a plane), it is common practice to use a rectangular
coordinate system in which the axes form a right-handed Cartesian set, the x -axis and the y -axis also lying on
the nominal surface, and the z -axis being in an outward direction (from the material to the surrounding
medium). This convention is adopted throughout the rest of this document.
ISO 21920-2:2021(E)
3.1.11
nesting index
N , N , N
is ic if
number or set of numbers indicating the relative level of nesting for a particular primary mathematical
model
Note 1 to entry: The cut-off wavelength for the Gaussian filter is an example of a nesting index.
Note 2 to entry: Using the different nesting indices, specific lateral scale components of a scale-limited profile are
extracted.
[SOURCE: ISO 16610-1:2015, 3.2.1, modified — definition and notes to entry revised.]
3.1.12
primary surface profile
surface profile trace obtained when a surface profile trace is represented as a specified primary
mathematical model with specified nesting index N
is
Note 1 to entry: In the ISO 21920 series, a profile S-filter is used to derive the primary surface profile from a
profile trace (e.g. mechanical profile). See Figure 6 and Annex H.
Note 2 to entry: For some applications, the profile S-filter is not used. In such cases, for example for multi-scale
analysis, the nesting index is equal to “zero”.
Note 3 to entry: In most situations, the primary surface profile can be derived with sufficient accuracy from
either the mechanical surface (the default choice), the electromagnetic surface or the auxiliary surface, using an
intersection plane perpendicular to the chosen type of surface and in a specified direction. See Figure 6.
NOTE The evaluation chain for the default case is indicated by the grey fill colour.
a
See 3.1.13.1 for profile S-filter.
b
See ISO 25178-2:2021, 3.1.6.1, for S-filter.
c
See ISO 25178-2:2021, 3.1.5, for primary surface.
Figure 6 — Definition of the primary surface and primary surface profile
3.1.13
profile filter
filtration operator applied to a profile
ISO 21920-2:2021(E)
3.1.13.1
profile S-filter
profile filter which removes small lateral scale components from a profile
Note 1 to entry: See Figure 7.
3.1.13.2
profile L-filter
profile filter which removes large lateral scale components from a profile
Note 1 to entry: Some profile L-filters are sensitive to form and require the profile F-operation first as a prefilter
before being applied.
Note 2 to entry: See Figure 7.
3.1.13.3
profile F-operation
operation which removes form from a profile
Note 1 to entry: See Figure 7.
Key
A small lateral scale (e.g. short wavelengths)
B large lateral scale (e.g. long wavelengths)
C scale axis
D amplitude axis
E lateral scale component extracted by the profile S-filter
F lateral scale component extracted by the profile F-operation
G lateral scale component extracted by the profile L-filter
H profile S-filter nesting index N
is
I profile F-operation nesting index N
if
J profile L-filter nesting index N
ic
Figure 7 — Relationships between the S-filter, L-filter and F-operation
ISO 21920-2:2021(E)
3.1.14
scale-limited profile
profile structure scale components between specified nesting indices
EXAMPLE A profile is scale-limited after applying a profile filter with a specified nesting index.
3.1.14.1
primary profile
P-profile
scale-limited profile at any position x derived from the primary surface profile by removing the form
using a profile F-operation with nesting index N
if
Note 1 to entry: In most cases, the primary profile can be derived with sufficient accuracy from the S-F surface
using an intersection plane perpendicular to the S-F surface and in a specified direction. See Figure 8.
Note 2 to entry: The primary profile is the basis for evaluation of the P-parameters (3.2.5). See Figures 9 and 10.
Note 3 to entry: The profile F-operation can be performed as a multi-stage operation, for example a combination
of a total least square fit and a profile L-filter.
Note 4 to entry: See Annex H for additional information.
NOTE The evaluation chain for the default case is indicated by the grey fill colour.
a
See ISO 25178-2:2021, 3.1.6.3, for F-operation.
b
See ISO 25178-2:2021, 3.1.7, for S-F surface.
Figure 8 — Primary profile derived from the primary surface profile (default) or S-F surface
3.1.14.2
waviness profile
W-profile
scale-limited profile at any position x derived from the primary profile by removing small-scale lateral
components by a specific type of profile S-filter with a nesting index N
ic
Note 1 to entry: The waviness profile is the basis for evaluation of the W-parameters (3.2.6). See Figures 9 and 10.
Note 2 to entry: The choice of filter settings for W-parameters is highly dependent on the functional requirements.
This is why no default tables for W-parameters are found in ISO 21920-3.
Note 3 to entry: See Annex H for additional information.
ISO 21920-2:2021(E)
3.1.14.3
roughness profile
R-profile
scale-limited profile at any position x derived from the primary profile by removing large-scale lateral
components by a specific type of profile L-filter with a nesting index N
ic
Note 1 to entry: The roughness profile is the basis for evaluation of the R-parameters (3.2.7). See Figures 9 and
10.
Note 2 to entry: See Annex H for additional information.
Key
A small lateral scale
B large lateral scale
C scale axis
D amplitude axis
E lateral scale component of primary surface profile
F lateral scale component of P-profile
G lateral scale component of W-profile
H lateral scale component of R-profile
I profile S-filter nesting index N
is
J profile F-operation nesting index N
if
K profile L-filter nesting index N
ic
Figure 9 — Relationship between the primary surface profile, P-profile, W-profile and R-profile
ISO 21920-2:2021(E)
Figure 10 — Measuring chain to determine the P-profile, W-profile and R-profile
3.1.15
reference line
line corresponding to a specific large lateral scale component
Note 1 to entry: The x -axis of the specification coordinate system (3.1.10) coincides with the reference line of the
assessed profile and the z -axis is oriented in an outward direction (from the material to the surrounding
medium). This convention is adopted throughout the rest of this document.
Note 2 to entry: The reference line for the primary profile and waviness profile are the large lateral scale
component of primary surface profile removed by the profile F-operation.
Note 3 to entry: The reference line for the roughness profile is the component of the primary profile removed by
the profile L-filter.
3.1.16
evaluation length
l
e
length in the direction of the x -axis used for identifying the geometrical structures characterizing the
scale-limited profile
Note 1 to entry: The traverse length is longer than the evaluation length.
Note 2 to entry: See 3.2.3 for evaluation length parameters.
Note 3 to entry: In ISO 4287, the evaluation length was given by l .
n
3.1.17
section length
l
sc
length in the direction of the x -axis used to obtain section length parameters (3.2.4)
Note 1 to entry: Default values of l are found in ISO 21920-3.
sc
3.1.18
number of sections
n
sc
integer number used to obtain section length parameters (3.2.4)
Note 1 to entry: Default values of n are found in ISO 21920-3.
sc
3.2 Geometrical parameter terms
ISO 21920-2:2021(E)
NOTE Parameter symbols are written with subscripts (e.g. R ) when used in formulae to avoid
q
misinterpretations of compound letters as an indication of multiplication between quantities. Parameter symbols
are written with lower-case suffixes (e.g. Rq ) when used in product documentation, drawings and data sheets.
3.2.1
field parameter
parameter defined from all the points on a scale-limited profile
3.2.2
feature parameter
parameter defined from a subset of predefined topographic features from the scale-limited profile
Note 1 to entry: For feature parameters, see Clause 5.
3.2.3
evaluation length parameter
parameter defined on the evaluation length
Note 1 to entry: See Clause 4, 5.2 and 5.3 for evaluation length parameters.
3.2.4
section length parameter
parameter defined on a set of section length
Note 1 to entry: See 5.1 for section length parameters.
3.2.5
P-parameter
parameter determined from the primary profile
3.2.6
W-parameter
parameter determined from the waviness profile
3.2.7
R-parameter
parameter determined from the roughness profile
Note 1 to entry: Formulae for parameter definitions are exemplarily given for R-parameters. P- and W-parameters
are defined in a similar manner, replacing the parameters related to the R-profile with those related to the
P-profile or W-profile. Default specification operators for the different types of parameter definitions can be
found in ISO 21920-3.
3.2.8
height
signed normal distance from the reference line to the scale-limited profile
Note 1 to entry: Where the scale-limited profile is below the reference line, the height has a negative value.
Note 2 to entry: This definition as an absolute coordinate applies when the term ‘height’ is used alone. Later
terms in this document include the word ‘height’ or ‘depth’ in their name, such as the maximum height Rz (see
5.1.6) or dale local depth (3.3.18). The definitions of some of those later terms use an alternative reference point
and/or refer to an unsigned distance in a specified direction from the reference point. See those definitions for
details.
3.2.9
depth
height multiplied by minus one
Note 1 to entry: Where the scale-limited profile is above the reference line, the depth has a negative value.
ISO 21920-2:2021(E)
Note 2 to entry: This definition as an absolute coordinate applies when the term ‘depth’ is used alone. Later terms
in this document include the word ‘height’ or ‘depth’ in their name, such as the maximum height Rz (see 5.1.6) or
dale local depth (3.3.18). The definitions of some of those later terms use an alternative reference point and/or
refer to an unsigned distance in a specified direction from the reference point. See those definitions for details.
3.2.10
ordinate value
zx()
height of the assessed scale-limited profile
3.2.11
local gradient
ddzx()/ x
first derivative of the scale-limited profile z with respect to the position x
Note 1 to entry: See Annex A for the determination of the gradient.
Note 2 to entry: The local gradient is also called slope.
3.2.12
local curvature
κ x
()
curvature of the scale-limited profile z with respect to the position x
ddzx() x
κ()x = (1)
1+ ddzx x
()()
()
Note 1 to entry: See Annex A and Annex B for the determination of the curvature.
Note 2 to entry: For most engineering surfaces, the local gradient (slope) is small, enabling a good approximation
of local curvature by the local second derivative κ()xz≅ dd()xx/ .
() ()
3.2.13
autocorrelation function
ft
()
ACFx
function which describes the correlation between a scale-limited profile z and the same profile spatial
shifted by t
x
zx −zz xt+ −zxd
()() ()()
x
∫
lt−
ex
l
ft()= (2)
ACFx
l
e
()zx()−zxd
∫
l
e
where
z is the arithmetic mean of the profile zx() over the evaluation length l ;
e
lx=∈{}R | mmax,()0 −tx≤≤ in()ll, −t is the overlap interval;
0 xe ex
tl< is the spatial shift.
xe
Note 1 to entry: See Figure 11 for an illustration of the overlap interval.
Note 2 to entry: The autocorrelation function is symmetrical in t , i.e. ft =−ft .
() ()
x ACFx ACFx
Note 3 to entry: Formula (2) is an unbiased estimator for the autocorrelation function.
ISO 21920-2:2021(E)
Note 4 to entry: Some disciplines use a shift-dependent Pearson correlation coefficient instead of the
autocorrelation function. It is defined by Formula (3).
zx −zz xt+ −zxd
()() ()()
x
∫
l
ρ ()t = with −≤11ρ ()t ≤ (3)
XX x XX x
2 22
()zx()−zxd ⋅+()zx()tz− dx
x
∫ ∫
l l
0 0
Key
A height C
overlap interval l
B
x -axis (reference line)
Figure 11 — Illustration of the overlap interval l
3.2.14
Fourier transformation
Fp
()
operator which transforms the scale-limited profile z into Fourier domain
l
e
−i2πpx
Fp()= zx() exd (4)
∫
where
i is the imaginary unit i =−1 ;
p
is the spatial frequency.
3.2.15
amplitude spectral density
fp()
ASD
absolute value of the Fourier transformation of the scale-limited profile z
fp = Fp (5)
() ()
ASD
where
is the Fourier transformation of the scale-limited profile z ;
Fp
()
p
is the spatial frequency.
ISO 21920-2:2021(E)
3.2.16
power spectral density
fp
()
PSD
function which describes the power of a scale-limited profile z in the Fourier domain
Fp()
fp()= (6)
PSD
l
e
where
is the Fourier transformation of the scale-limited profile z ;
Fp()
p
is the spatial frequency.
Note 1 to entry: The power spectral density fulfils Formula (7):
l
∞
e
zx()ddxf= ()pp (7)
PSD
∫∫
l
e
0 −∞
3.3 Geometrical feature terms
3.3.1
segmentation
method which partitions a scale-limited profile into distinct features
Note 1 to entry: There are three types of segmentation:
— for the parameters based on peak heights and pit depths (see 5.1), the segmentation is realized by identification
of the hills (3.3.11) and dales (3.3.17) by determination of the positions where the ordinate values change
their sign or are equal to zero;
— for the parameters based on profile elements (see 5.2), the segmentation is realized by the crossing-the-line
segmentation (3.3.2);
— for the parameters based on feature characterization (see 5.3), the segmentation is realiz
...
Le document SIST EN ISO 21920-2:2022 est une référence essentielle dans le domaine des spécifications géométriques des produits (GPS), particulièrement en ce qui concerne la texture de surface sous la forme de profil. Ce standard fournit une nomenclature claire, des définitions précises, ainsi que des paramètres essentiels pour la détermination de la texture de surface utilisant des méthodes de profil. L'un des principaux points forts de cette norme réside dans sa capacité à uniformiser le langage utilisé dans l'évaluation de la texture de surface, ce qui peut considérablement faciliter la communication entre les différents acteurs de l'industrie. En se basant sur des termes et définitions standardisés, elle permet d'éliminer les malentendus pouvant découler de variations terminologiques dans différents pays ou secteurs. Cela rend cette norme hautement pertinente pour assurer la cohérence et la qualité dans les processus de fabrication où la texture de surface revêt une importance cruciale. En outre, les modifications apportées par rapport aux documents ISO précédents, comme décrit dans l'Annexe I, reflètent une volonté d'adapter les standards aux évolutions technologiques et industrielles. Cela garantit que les utilisateurs de cette norme disposent des outils les plus récents pour évaluer et mesurer les textures de surface. L'intégration de l'Annexe J, qui donne un aperçu des standards de profil et de surface en relation avec le modèle matriciel de GPS, et l'Annexe K, qui établit les relations de ce document avec le modèle GPS, sont des ajouts significatifs qui renforcent la compréhension globale des standards GPS. Cela souligne également l'importance de l'interconnexion des différents aspects de la géométrie des produits. En somme, le SIST EN ISO 21920-2:2022 se positionne comme un document clé pour les professionnels cherchant à garantir la qualité et la précision dans l'évaluation de la texture de surface, tout en contribuant à une compréhension partagée et standardisée dans le domaine de la spécification géométrique.
SIST EN ISO 21920-2:2022 문서는 표면 텍스처의 프로파일 방법에 따른 정의와 파라미터를 명확하게 규정하는 중요한 표준입니다. 이 표준은 표면 텍스처 측정의 기초를 제공하는 데 필수적인 요소로, 정밀한 제품 설계와 품질 관리를 위해 꼭 필요합니다. 이 표준의 강점 중 하나는 용어와 정의가 체계적으로 정리되어 있어, 관련 산업에서 혼돈 없이 쉽고 명확하게 적용될 수 있다는 점입니다. 이는 제조업체가 제품의 표면 품질을 일관되게 평가하는 데 기여합니다. 문서에는 표면 텍스처 파라미터에 대한 구체적인 기준이 포함되어 있어, 다양한 응용 프로그램에서 신뢰할 수 있는 결과를 도출할 수 있습니다. 또한 이 문서는 이전 ISO 프로파일 문서와의 주요 변경사항이 부록 I에 설명되어 있어, 사용자는 새로운 기준에 대한 이해를 돕는 데 유용합니다. 아울러, GPS 매트릭스 모델의 프로파일 및 면적 기준에 대한 개요가 부록 J에 제시되어 있어, 이 표준의 위치를 명확하게 파악할 수 있습니다. 결론적으로, SIST EN ISO 21920-2:2022 표준은 표면 텍스처 평가에 있어 필수적인 기준을 제공하며, 제조업계에서의 적용 가능성을 더욱 확장하는 데 기여할 것입니다. 이는 표준화의 중요성을 더욱 부각시키며, 제품 품질 향상에 중요한 역할을 하고 있습니다.
The standard EN ISO 21920-2:2022 provides a comprehensive framework for geometrical product specifications (GPS) specifically focusing on surface texture by profile methods. The document serves as a critical resource for professionals involved in the determination of surface texture parameters, ensuring clarity through well-defined terms and definitions. One of the primary strengths of EN ISO 21920-2:2022 is its meticulous attention to precision in specifying surface texture parameters. This standard significantly aids in harmonizing the language used across various industries, thereby enhancing communication and reducing misinterpretations related to surface texture specifications. The inclusion of updated definitions reflects contemporary practices and technological advancements in surface measurement techniques. The relevance of this standard is underscored by its role in supporting quality assurance processes and ensuring product performance in manufacturing. By standardizing the parameters used in evaluating surface texture, industries can achieve greater consistency and reliability in their products. Furthermore, the document addresses previous gaps identified in earlier ISO profile standards, as highlighted in Annex I, making it an essential update for those familiar with earlier documentation. Annexes J and K provide a broader context regarding the integration of surface texture profile measurements within the GPS matrix model. This contextualization is beneficial for professionals seeking to understand the relationship between different standards and how they interact within the overarching geometrical product specifications framework. Overall, EN ISO 21920-2:2022 stands out as a vital standard for industries that prioritize precision in surface texture specifications, fostering improved quality management and operational efficiencies across manufacturing processes.
標準EN ISO 21920-2:2022は、表面テクスチャのプロファイルに関する用語、定義、およびパラメータを定めるものであり、その適用範囲は広範囲にわたります。この文書は、表面テクスチャをプロファイル手法で決定するための標準的なフレームワークを提供しており、製造業や品質管理において重要な役割を果たします。 本標準の大きな強みは、以前のISOプロファイル文書に対する主要な変更点が附属書Iで整理されていることです。これにより、ユーザーは新しい基準が過去の基準に対してどのように進化したかを容易に把握でき、効果的な適応が可能となります。また、附属書JではGPSマトリックスモデルにおけるプロファイルおよびエリア基準の概要が提供されており、全体的な文脈での理解を深める手助けをしています。 さらに附属書Kでは、本標準とGPSマトリックスモデルとの関係が明示されており、これにより表面テクスチャ解析が他の幾何公差標準とどのように連携しているかが示されています。これらの関連情報は、業界内での実用性を高め、標準化による一貫性と信頼性を持った測定が可能になる点で非常に重要です。 全体として、EN ISO 21920-2:2022は表面テクスチャに関する基準を明確に定義し、プロファイル法に基づく測定の標準化を推進するものであり、製造業における品質管理の信頼性を確保するための重要な指針となるでしょう。この標準は、製品の表面品質向上に寄与するだけでなく、国際的な取引における共通の言語を提供する役割も果たします。
Die Norm EN ISO 21920-2:2022 behandelt die geometrischen Produktspezifikationen (GPS) im Bereich der Oberflächenbeschaffenheit und bietet eine umfassende Grundlage für die Terminologie, Definitionen und Parameter zur Bestimmung der Oberflächenstruktur mittels Profilmethoden. Diese Norm ist entscheidend für die Industrien, in denen Oberflächenbeschaffenheit von zentraler Bedeutung ist, da sie die einheitliche Anwendung von Begrifflichkeiten und Messmethoden fördert. Ein herausragendes Merkmal der Norm ist ihre detaillierte Aufschlüsselung der Oberflächenparameter, die für die Bewertung der Oberflächenbeschaffenheit von Bedeutung sind. Die Einführung von klaren und präzisen Definitionen ermöglicht es Fachleuten, Missverständnisse zu vermeiden und sorgt für Konsistenz in der Kommunikation über Oberflächenqualitäten. Dies trägt zur Verbesserung der Produktions- und Prüfverfahren bei. Ein weiterer wesentlicher Vorteil dieser Norm ist die Erörterung der wichtigsten Änderungen im Vergleich zu früheren ISO-Dokumenten, die im Anhang I aufgeführt sind. Diese Änderungen tragen zur Aktualität und Relevanz der Norm bei, da sie an die aktuellen technologischen Entwicklungen und Anforderungen der Industrie angepasst sind. Zudem bietet der Überblick über Profil- und Flächenstandards im GPS-Matrixmodell im Anhang J eine wertvolle Orientierungshilfe für die Integration dieser Norm in die bestehende Normenlandschaft. Die Beziehung der Norm zum GPS-Matrixmodell, die im Anhang K behandelt wird, ist ebenfalls von großer Bedeutung, da sie die Verknüpfung der verschiedenen Normen und deren Anwendung in der Praxis verdeutlicht. Dies stärkt das Verständnis für die Rolle der Norm im Gesamtkontext der geometrischen Produktspezifikationen. Insgesamt bietet die EN ISO 21920-2:2022 eine robuste und relevante Grundlage für die Standardisierung im Bereich der Oberflächenbeschaffenheit durch Profilmethoden, indem sie klare Definitionen und Parameter bereitstellt, die für die Qualitätssicherung und die technische Kommunikation unerlässlich sind.
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