SIST EN ISO 2692:2007
(Main)Geometrical product specifications (GPS) - Geometrical tolerancing - Maximum material requirement (MMR), least material requirement (LMR) and reciprocity requirement (RPR) (ISO 2692:2006)
Geometrical product specifications (GPS) - Geometrical tolerancing - Maximum material requirement (MMR), least material requirement (LMR) and reciprocity requirement (RPR) (ISO 2692:2006)
This Internation Standard is a Geometrical product specification (GPS) standard and is to be regarded as a general GPS standard (see ISO/TR 14638). It influences the chain links 1, 2 and 3 of the chain of standards on size of linear features of size and form, orientation or location of derived features based on "features of size".
Geometrische Produktspezifikation (GPS) - Form- und Lagetolerierung - Maximum-Material-Bedingung (MMR), Minimum-Material-Bedingung (LMR) und Reziprozitätsbedingung (RPR) (ISO 2692:2006)
Diese Internationale Norm definiert die Maximum-Material-Bedingung, die Minimum-Material-Bedingung und die Reziprozitätsbedingung und legt ihre Anwendungen fest.
Diese Anforderungen dienen zur Steuerung bestimmter Funktionen von Werkstücken, bei denen eine Abhängigkeit von Maß und Geometrie vorhanden ist, z. B. zur Erfüllung der Funktionen zusammengebauter Teile (für die Maximum-Material-Bedingung) und zur Erfüllung der Funktion Mindest-Wandstärke (für Minimum-Material-Bedingung). Die Maximum-Material-Bedingung und die Minimum-Material-Bedingung werden jedoch auch zur Erfüllung anderer funktionaler Anforderungen genutzt.
Spécification géométrique des produits (GPS) - Tolérancement géométrique - Exigence du maximum de matiere (MMR), exigence du minimum de matiere (LMR) et exigence de réciprocité (RPR) (ISO 2692:2006)
L'ISO 2692:2006 définit l'exigence du maximum de matière, l'exigence du minimum de matière et l'exigence de réciprocité, et en précise les applications.
L'objectif de ces exigences est de contrôler les fonctions spécifiques de pièces où la taille et la géométrie sont interdépendantes, afin d'assurer, par exemple, l'assemblage des pièces (dans le cas de l'exigence du maximum de matière) et une épaisseur de paroi minimale (dans le cas de l'exigence du minimum de matière). Cependant, l'exigence du maximum de matière et l'exigence du minimum de matière peuvent être employées pour respecter d'autres exigences fonctionnelles de conception.
Specifikacija geometrijskih veličin izdelka – Toleriranje geometrijskih veličin – Zahteva po maksimalnem materialu, zahteva po minimalnem materialu in zahteva po materialni usklajenosti (ISO 2692:2006)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 2692:2007
01-april-2007
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=DKWHYDSRPDNVLPDOQHPPDWHULDOX]DKWHYDSRPLQLPDOQHPPDWHULDOXLQ]DKWHYD
SRPDWHULDOQLXVNODMHQRVWL ,62
Geometrical product specifications (GPS) - Geometrical tolerancing - Maximum material
requirement (MMR), least material requirement (LMR) and reciprocity requirement (RPR)
(ISO 2692:2006)
Geometrische Produktspezifikation (GPS) - Form- und Lagetolerierung - Maximum-
Material-Bedingung (MMR), Minimum-Material-Bedingung (LMR) und
Reziprozitätsbedingung (RPR) (ISO 2692:2006)
Spécification géométrique des produits (GPS) - Tolérancement géométrique - Exigence
du maximum de matiere (MMR), exigence du minimum de matiere (LMR) et exigence de
réciprocité (RPR) (ISO 2692:2006)
Ta slovenski standard je istoveten z: EN ISO 2692:2006
ICS:
01.100.20 Konstrukcijske risbe Mechanical engineering
drawings
SIST EN ISO 2692:2007 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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EUROPEAN STANDARD
EN ISO 2692
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2006
ICS 01.100.20
English Version
Geometrical product specifications (GPS) - Geometrical
tolerancing - Maximum material requirement (MMR), least
material requirement (LMR) and reciprocity requirement (RPR)
(ISO 2692:2006)
Spécification géométrique des produits (GPS) - Geometrische Produktspezifikation (GPS) - Form- und
Tolérancement géométrique - Exigence du maximum de Lagetolerierung - Maximum-Material-Bedingung (MMR),
matière (MMR), exigence du minimum de matière (LMR) et Minimum-Material-Bedingung (LMR) und
exigence de réciprocité (ISO 2692:2006) Reziprozitätsbedingung (RPR) (ISO 2692:2006)
This European Standard was approved by CEN on 25 November 2006.
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 Central Secretariat 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 Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 2692:2006: E
worldwide for CEN national Members.
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EN ISO 2692:2006 (E)
Foreword
This document (EN ISO 2692:2006) 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 June 2007, and conflicting national
standards shall be withdrawn at the latest by June 2007.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Endorsement notice
The text of ISO 2692:2006 has been approved by CEN as EN ISO 2692:2006 without any
modifications.
2
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INTERNATIONAL ISO
STANDARD 2692
Second edition
2006-12-15
Geometrical product specifications
(GPS) — Geometrical tolerancing —
Maximum material requirement (MMR),
least material requirement (LMR) and
reciprocity requirement (RPR)
Spécification géométrique des produits (GPS) — Tolérancement
géométrique — Exigence du maximum de matière (MMR), exigence du
minimum de matière (LMR) et exigence de réciprocité (RPR)
Reference number
ISO 2692:2006(E)
©
ISO 2006
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ISO 2692:2006(E)
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ii © ISO 2006 – All rights reserved
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ISO 2692:2006(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Maximum material requirement, MMR and least material requirement, LMR. 5
4.1 General. 5
4.2 Maximum material requirement, MMR. 5
4.3 Least material requirement, LMR. 7
5 Reciprocity requirement, RPR. 9
5.1 General. 9
5.2 Reciprocity requirement and maximum material requirement . 9
5.3 Reciprocity requirement and least material requirement. 9
Annex A (informative) Examples of tolerancing with Ⓜ, Ⓛ and Ⓡ. 10
Annex B (informative) Concept diagram. 29
Annex C (informative) Relation to the GPS matrix model. 30
Bibliography . 31
© ISO 2006 – All rights reserved iii
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ISO 2692:2006(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 2692 was prepared by Technical Committee ISO/TC 213, Dimensional and geometrical product
specifications and verification.
This second edition cancels and replaces the first edition (ISO 2692:1988), which has been technically revised.
It also incorporates the Amendment ISO 2692:1988/Amd.1:1992.
iv © ISO 2006 – All rights reserved
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ISO 2692:2006(E)
Introduction
0.1 General
This International Standard is a Geometrical product specification (GPS) standard and is to be regarded as a
general GPS standard (see ISO/TR 14638). It influences the chain links 1, 2 and 3 of the chain of standards
on size of linear “features of size” and form, orientation or location of derived features based on “features of
size”.
For more detailed information of the relation of this International Standard to the GPS matrix model, see
Annex C.
This International Standard covers some frequently occurring workpiece functional cases in design and
tolerancing. The “maximum material requirement”, MMR, covers “assembleability” and the “least material
requirement”, LMR, covers, for example, “minimum wall thickness” of a part. Each requirement (MMR and
LMR) combines two independent tolerance requirements into one collective requirement, which more
accurately simulates the intended function of the workpiece. In some cases of both MMR and LMR, the
“reciprocity requirement”, RPR, can be added.
0.2 Information about maximum material requirement, MMR
The assembly of parts depends on the combined effect of:
a) the size (of one or more extracted features of size), and
b) the geometrical deviation of the (extracted) features and their derived features, such as the pattern of bolt
holes in two flanges and the bolts securing them.
The minimum assembly clearance occurs when each of the mating features of size is at its maximum material
size (e.g. the largest bolt size and the smallest hole size) and when the geometrical deviations (e.g. the form,
orientation and location deviations) of the features of size and their derived features (median line or median
surface) are also at their maximum. Assembly clearance increases to a maximum when the sizes of the
assembled features of size are furthest from their maximum material sizes (e.g. the smallest shaft size and the
largest hole size) and when the geometrical deviations (e.g. the form, orientation and location deviations) of
the features of size and their derived features are zero. It therefore follows that if the sizes of one mating part
do not reach their maximum material size, the indicated geometrical tolerance of the features of size and their
derived features may be increased without endangering the assembly to the other part.
This assembly function is controlled by the maximum material requirement. The collective requirement is
indicated on drawings by the symbol Ⓜ.
0.3 Information about least material requirement, LMR
The least material requirement is designed to control, for example, the minimum wall thickness, thereby
preventing breakout (due to pressure in a tube), the maximum width of a series of slots, etc. It is indicated on
drawings by the symbol Ⓛ. The least material requirement is also characterised by a collective requirement
for the size of a feature of size, the geometrical deviation of the feature of size (form deviations) and the
location of its derived feature.
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ISO 2692:2006(E)
0.4 Information about reciprocity requirement, RPR
The reciprocity requirement is an additional requirement, which may be used together with the maximum
material requirement and the least material requirement in cases where it is permitted — taking into account
the function of the toleranced feature(s) — to enlarge the size tolerance when the geometrical deviation on the
actual workpiece does not take full advantage of, respectively, the maximum material virtual condition or the
least material virtual condition.
The reciprocity requirement is indicated on the drawing by the symbol Ⓡ.
0.5 General information about terminology and figures
The terminology and tolerancing concepts in this International Standard have been updated to conform to
GPS terminology, notably that in ISO 286-1:1998, ISO 14405:—, ISO 14660-1:1999, ISO 14660-2:1999 and
ISO/TS 17450-1:2005.
vi © ISO 2006 – All rights reserved
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INTERNATIONAL STANDARD ISO 2692:2006(E)
Geometrical product specifications (GPS) — Geometrical
tolerancing — Maximum material requirement (MMR), least
material requirement (LMR) and reciprocity requirement (RPR)
1 Scope
This International Standard defines the maximum material requirement, the least material requirement and the
reciprocity requirement, and specifies their applications.
These requirements are used to control specific functions of workpieces where size and geometry are
interdependent, e.g. to fulfil the functions “assembly of parts” (for maximum material requirement) and
“minimum wall thickness” (for least material requirement). However, the maximum material requirement and
least material requirement are also used to fulfil other functional design requirements.
2 Normative references
The following referenced documents are indispensable for the application 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 286-1:1988, ISO system of limits and fits — Part 1: Bases of tolerances, deviations and fits
ISO 1101:2004, Geometrical Product Specifications (GPS) — Geometrical tolerancing — Tolerances of form,
orientation, location and run-out
1)
ISO 5459:— , Geometrical product specifications (GPS) — Geometrical tolerancing — Datums and datum-
systems
2)
ISO 14405:— , Geometrical Product Specifications (GPS) — Dimensional tolerancing — Linear sizes
ISO 14660-1:1999, Geometrical Product Specifications (GPS) — Geometrical features — Part 1: General
terms and definitions
ISO 14660-2:1999, Geometrical Product Specifications (GPS) — Geometrical features — Part 2: Extracted
median line of a cylinder and a cone, extracted median surface, local size of an extracted feature
ISO/TS 17450-1:2005, Geometrical Product Specifications (GPS) — General concepts — Part 1: Model for
geometrical specification and verification
1) To be published. (Revision of ISO 5459:1981)
2) To be published.
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ISO 2692:2006(E)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 286-1:1998, ISO 14405:—,
ISO 14660-1:1999, ISO 14660-2:1999, ISO/TS 17450-1:2005 and the following apply.
3.1
feature of size
geometrical shape defined by a linear or angular dimension which is a size
[ISO 14660-1:1999]
3.2
derived feature
centrepoint, median line or median surface from one or more integral features
[ISO 14660-1:1999]
3.3
integral feature
surface or line on a surface
NOTE An integral feature is intrinsically defined.
[ISO 14660-1:1999]
3.4
maximum material condition
MMC
state of the considered extracted feature, where the feature of size is at that limit of size where the material of
the feature is at its maximum everywhere, e.g. minimum hole diameter and maximum shaft diameter
NOTE 1 The term maximum material condition, MMC, is used in this International Standard to indicate, at ideal or
nominal feature level (see ISO/TS 17450-1 and ISO 14660-1 respectively), which upper or lower limit of the requirement is
concerned.
NOTE 2 The size of the extracted feature at maximum material condition, MMC, can be defined by default, or by
several special definitions of the size of the extracted feature (see ISO 14405 and ISO 14660-2).
NOTE 3 The maximum material condition, MMC, as defined in this International Standard, can be used unambiguously
with any definition of size of the extracted feature.
3.5
maximum material size
MMS
l
MMS
dimension defining the maximum material condition of a feature
See Annex A.
NOTE 1 Maximum material size, MMS, can be defined by default or by one of several special definitions of the size of
the extracted feature (see ISO 14405 and ISO 14660-2).
NOTE 2 In this International Standard, maximum material size, MMS is used as a numerical value, therefore no
specific definition of the extracted size is needed to permit unambiguous use of maximum material size, MMS.
3.6
least material condition
LMC
state of the considered extracted feature, where the feature of size is at that limit of size where the material of
the feature is at its minimum everywhere, e.g. maximum hole diameter and minimum shaft diameter
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ISO 2692:2006(E)
NOTE 1 The term least material condition, LMC, is used in this International Standard to indicate, at the ideal or
nominal feature level (see ISO/TS 17450-1 and ISO 14660-1 respectively), which end (upper or lower) of the requirement
is concerned.
NOTE 2 The size at least material condition, LMC, can be defined by default or by several special definitions of the size
of extracted feature (see ISO 14405 and ISO 14660-2).
NOTE 3 The least material condition, LMC, as defined in this International Standard, can be used unambiguously with
any definition of size of the extracted feature.
3.7
least material size
LMS
l
LMS
dimension defining the least material condition of a feature
See Annex A.
NOTE 1 Least material size, LMS, can be defined by default or by one of several special definitions of the size of the
extracted feature (see ISO 14405 and ISO 14660-2).
NOTE 2 In this International Standard, least material size, LMS, is used as a numerical value, therefore no specific
definition of the extracted size is needed to permit unambiguous use of least material size, LMS.
3.8
maximum material virtual size
MMVS
l
MMVS
size generated by the collective effect of the maximum material size, MMS, of a feature of size and the
geometrical tolerance (form, orientation or location) given for the derived feature of the same feature of size
NOTE 1 Maximum material virtual size, MMVS, is a parameter for size used as a numerical value connected to
maximum material virtual condition, MMVC.
NOTE 2 For external features, MMVS is the sum of MMS and the geometrical tolerance, whereas for internal features,
it is the difference between MMS and the geometrical tolerance.
NOTE 3 The MMVS for external features of size, l , is given by Equation (1):
MMVS,e
ll=+δ
MMVS,e MMS (1)
and the MMVS for internal features of size, l , is given by Equation (2):
MMVS,i
ll=−δ
MMVS,i MMS (2)
where
l is the maximum material size
MMS
δ is the geometrical tolerance.
3.9
maximum material virtual condition
MMVC
state of associated feature of maximum material virtual size, MMVS
See Annex A.
NOTE 1 Maximum material virtual condition, MMVC, is a perfect form condition of the feature.
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ISO 2692:2006(E)
NOTE 2 Maximum material virtual condition, MMVC, includes an orientation constraint (in accordance with ISO 1101
and ISO 5459) of the associated feature when the geometrical tolerance is a orientation tolerance (see Figure A.3).
Maximum material virtual condition, MMVC, includes a location constraint (in accordance with ISO 1101 and ISO 5459) of
the associated feature when the geometrical tolerance is a location tolerance (see Figure A.4).
3.10
least material virtual size
LMVS
l
LMVS
size generated by the collective effect of the least material size, LMS, of a feature of size and the geometrical
tolerance (form, orientation or location) given for the derived feature of the same feature of size
NOTE 1 Least material virtual size, LMVS, is a parameter for size used as a numerical value connected to least
material virtual condition, LMVC.
NOTE 2 For external features, LMVS is the difference between LMS and the geometrical tolerance, whereas for
internal features, it is the sum of LMS and the geometrical tolerance.
NOTE 3 The LMVS for external features of size, l , is given by Equation (3):
LMVS,e
ll=−δ
LMVS,e LMS (3)
and the MMVS for internal features of size, l , is given by Equation (4):
LMVS,i
ll=+δ
LMVS,i LMS (4)
where
l is the least material size
LMS
δ is the geometrical tolerance.
3.11
least material virtual condition
LMVC
state of associated feature of least material virtual size, LMVS
See Figures A.5, A.8 and A.9.
NOTE 1 Least material virtual condition, LMVC, is a perfect form condition of the feature.
NOTE 2 Least material virtual condition, LMVC, includes a location constraint (in accordance with ISO 1101 and
ISO 5459) of the associated feature when the geometrical tolerance is a location tolerance (see Figure A.5).
3.12
maximum material requirement
MMR
requirement for a feature of size, defining a geometrical feature of the same type and of perfect form, with a
given value for the intrinsic characteristic (dimension) equal to MMVS, which limits the non-ideal feature on
the outside of the material
NOTE 1 Maximum material requirement, MMR, is used to control the assembleability of a workpiece.
NOTE 2 See also 4.2.
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ISO 2692:2006(E)
3.13
least material requirement
LMR
requirement for a feature of size, defining a geometrical feature of the same type and of perfect form, with a
given value for the intrinsic characteristic (dimension) equal to LMVS, which limits the non-ideal feature on the
inside of the material
NOTE 1 Least material requirements, LMR, are used in pairs, e.g. to control the minimum wall thickness between two
symmetrical or coaxially located similar features of size.
NOTE 2 See also 4.3.
3.14
reciprocity requirement
RPR
additional requirement for a feature of size used as an addition to the maximum material requirement, MMR,
or the least material requirement, LMR to indicate that the size tolerance is increased by the difference
between the geometrical tolerance and the actual geometrical deviation
4 Maximum material requirement, MMR and least material requirement, LMR
4.1 General
The maximum material requirement, MMR, and the least material requirement, LMR, take into account the
mutual relationship of the size and the geometrical tolerance of interrelated features. These requirements can
be applied exclusively in order to combine requirements for the size of features of size and the geometrical
tolerance for the derived feature(s) of the feature(s) of size.
NOTE 1 This edition of this International Standard only covers features of size of type cylinder and type two opposite
parallel plane surfaces. Consequently, the only possible derived features are median lines and median surfaces.
When maximum material requirement, MMR, or least material requirement, LMR, is specified, the two
requirements (size and geometrical tolerance) are transformed into one collective requirement. The collective
requirement concerns only the integral feature, which in this International Standard relates to the surface(s) of
the feature(s) of size(s).
NOTE 2 In the past, the maximum material requirement, MMR, was referred to as the maximum material principle,
MMP.
When no modifiers (Ⓛ, Ⓜ, Ⓡ) are applied to the toleranced feature, the definitions of size of extracted feature
in ISO 14405 and ISO 14660-2 apply.
When no modifiers (Ⓛ, Ⓜ, Ⓡ) are applied to the datum, ISO 5459 applies.
4.2 Maximum material requirement, MMR
4.2.1 Maximum material requirement for toleranced features
The maximum material requirement for toleranced features results in four independent requirements:
a) a requirement for the upper limit of the local size [see Rules A 1) and A 2)];
b) a requirement for the lower limit of the local size [see Rules B 1) and B 2)];
c) a requirement for the surface non-violation of the MMVC (see Rule C);
d) a requirement for when more than one feature is involved (see Rule D).
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ISO 2692:2006(E)
When the maximum material requirement, MMR, applies to the toleranced feature, it is indicated on drawings
by the symbol Ⓜ placed after the geometrical tolerance of the derived feature of the feature of size
(toleranced feature) in the tolerance indicator.
In this case, it specifies for the surface(s) (of the feature of size) the following rules.
⎯ Rule A The extracted local sizes of the toleranced feature shall be:
1) equal to or smaller than the maximum material size, MMS, for external features;
2) equal to or larger than the maximum material size, MMS, for internal features.
NOTE 1 This rule can be altered by the indication of reciprocity requirement, RPR, with the symbol Ⓡ after the
symbol Ⓜ (see Clause 5 and Figure A.1).
⎯ Rule B The extracted local sizes of the toleranced feature shall be:
1) equal to or larger than the least material size, LMS, for external features [see Figures A.2 a), A.3 a),
A.4 a), A.6 a), A.7 a), A.10 and A.11];
2) equal to or smaller than the least material size, LMS, for internal features [see Figures A.2 b), A.3 b),
A.4 b), A.6 b), A.7 b), A.10 and A.11].
⎯ Rule C The maximum material virtual condition, MMVC, of the toleranced feature shall not be violated
by the extracted (integral) feature (see Figures A.2, A.3, A.4, A.6, A.7, A.10 and A.11).
NOTE 2 Use of other constraints on size at maximum material condition, MMC, e.g. envelope requirement Ⓔ
(previously also known as the Taylor Principle), can result in superfluous requirements, not necessary for the function of
the feature(s) (assembleability). Use of other such constraints and size definitions reduces the technical and economic
advantage of maximum material requirement, MMR.
NOTE 3 The indication 0 Ⓜ has the same meaning as envelope requirement Ⓔ when the geometrical specification is a
form tolerance.
⎯ Rule D When the toleranced features (in cases of more than one features) are controlled by the same
tolerance indication, or when the geometrical specification is orientation or location, the maximum
material virtual condition(s), MMVC(s), of the toleranced feature(s) are in theoretical exact location(s) and
orientation(s) relative to each other and to the datum(s), as applicable (see Figures A.6, A.7, A.10 and
A.11).
4.2.2 Maximum material requirement for related datum features
The maximum material requirement for datum features results in three independent requirements:
a) a requirement for the surface non-violation of the MMVC (see Rule E);
b) a requirement for MMS when there is no geometrical tolerance or when there is a geometrical tolerance
not followed by the symbol Ⓜ (see Rule F);
c) a requirement for MMS when there is a geometrical tolerance of form followed by the symbol Ⓜ (see
Rule G).
When the maximum material requirement, MMR, applies to the datum feature, it is indicated on drawings by
the symbol Ⓜ placed after the datum letter(s) in the tolerance indica
...
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