ISO14405-1999 Dimensional and geometrical product

COMMITTEE DRAFT ISO/CD 14405

COMMITTEE DRAFT

Date

Reference number

1999-09-17

ISO/TC 213

N 295

Supersedes document

WARNING: This document is not an International Standard. It is distributed for review and comment. It is subject to change without notice and may not be referred to as an International Standard.

Circulated to P- and O-members, and to technical committees and organizations in liaison for:

ISO/TC 213 Title

discussion at

Dimensional and geometrical product specifications and verification

[venue/date of meeting]

Secretariat

[date]

DS

comments by 1999-12-17

approval for registration as a DIS in accordance with 2.5.6 of part 1 of the ISO/IEC Directives, by

1999-12-17 [date]

(P-members vote only: ballot form attached) P-members of the technical committee or subcommittee concerned have an obligation to vote.

Title (English)

Geometrical product specifications (GPS) — Geometrical tolerancing — Linear size Title (French)

Spécification géométrique des produits (GPS) — Tolérancement géométrique — Taille linéaire Reference language version:

English

French

Russian

Introductory note

This committee draft has been submitted for ballot according to ISO/TC 213 N 283E, Resolution 357 (Vienna 12/1999), adopted at the 7th plenary meeting in Vienna, Austria, on 9 July 1999.

Copyright notice This ISO document is a committee draft and is copyright protected by ISO. While the reproduction of committee drafts in any form for use by participants in the ISO standards development process is permitted without prior permission from ISO, neither this document nor any extract from it may be reproduced, stored or transmitted in any form for any other purpose without prior written permission from ISO. Requests for permission to reproduce this document for the purpose of selling it should be addressed to the secretariat indicated above or to ISO’s member body in the country of the requester.

Reproduction for sales purposes may be subject to royalty payments or a licensing agreement.

Violators may be prosecuted. © ISO 1999 – All rights reserved

FORM 7 (ISO) Version/V97.1.2

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Contents 1 Scope................................................................................................................................................................. 1 2 Normative references........................................................................................................................................ 1 3 Definitions......................................................................................................................................................... 2 4 Symbols ............................................................................................................................................................ 4 5 Default definition of size .................................................................................................................................. 4 6 Limits of size..................................................................................................................................................... 5 7 Drawing indications for special definitions (non default definition) ............................................................. 5 7.1 General ........................................................................................................................................................... 5 7.2 Alternative default definition for the entire drawing.................................................................................... 5 7.3 Individual special definition.......................................................................................................................... 5 8 Writing are reading rules.................................................................................................................................. 6 8.1 Writing rules................................................................................................................................................... 6 8.2 Reading rules ................................................................................................................................................. 6 9 Simplifications of indications - Envelope requirement .................................................................................. 7 Annex A (informative) Concept diagram............................................................................................................. 8 Annex B (informative) Former Practice................................................................................................................ 9 Annex C (informative) Relation to the GPS matrix model ............................................................................... 10 Bibliography ...................................................................................................................................................... 11

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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 3.

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.

ISO 14405 was prepared by Technical Committee ISO/TC 213, Dimensional and geometrical product specifications and verification.

Annexes A, B and C are for information only.

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Introduction 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 chain links 1 to 3 of the chain of standards on size.

For more detailed information of the relation of this standard to other standards and the GPS matrix model see annex C. Produced workpieces exhibit deviations from the ideal geometric form. The real value of the dimension of a feature of size is depending on the form deviations and on the specific type of size applied.

The type of size to be applied to a feature of size depends on the function of the workpiece.

The type of size can be indicated on the drawing by a modifier for controlling the feature definition and evaluation method to be used.

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COMMITTEE DRAFT

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ISO/CD 14405

Geometrical product Specification (GPS) — Geometrical tolerancing — Linear size

1 Scope This International Standard establishes the default definition of size, special definitions and drawing indications for the following linear sizes of features of size of types cylinder or two opposite parallel planes : 

local size  local size of an extracted cylinder  local size of two parallel extracted surfaces  local size defined by a sphere  global linear size  least squares size  maximum inscribed size  minimum circumscribed size  calculation size  circumference diameter size  area diameter size  statistical size This International Standard controls the meaning of linear sizes indicated as + and/or - limit deviations, e.g.

0/-0,019, as well as ISO size tolerance code according to ISO 286, e.g. h6 (see figure 7).

2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revision of, any of these publications do not apply. However, parties of agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative documents referred to applies. Members of IEC and ISO maintain registers of currently valid International Standards.

ISO 286-1:1988, ISO system of limits and fits  Part 1: Bases of tolerances, deviations and fits ISO 8015:1985, Technical drawings  Fundamental tolerancing principle ISO 14660-1:1999, Geometrical product specification (GPS)  Geometrical features  Part 1: General terms and definitions ISO 14660-2:1999, Geometrical product specification (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: verification

1),

Geometrical product specification (GPS)  Model for geometric specification and

1) Under preparation

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3 Definitions For the purposes of this International Standard, definitions of ISO 14660-1, ISO 14660-2, ISO/TS 17450-1 and the following apply.

3.1 feature of size [ISO 14660-1] 3.2 size value either of a local size, or of a global linear size, or of a calculation size, or of a statistical size NOTE

The size can only be defined on features of size.

3.2.1 local linear size (of an extracted feature) either a distance between two points or a local size defined by a sphere NOTE 1 NOTE 2 NOTE 3

For a given feature, an infinity of local sizes exists.

When a local size corresponds to a distance between two points, it is called « two-point size ».

In the following , « local linear size » is referred to only as « local size ».

3.2.1.1 local size of an extracted cylinder [ISO 14660-2] 3.2.1.2 local size of two parallel extracted surfaces [ISO 14660-2] 3.2.1.3 local size defined by a sphere (of an extracted feature) value of the maximum inscribed diameter of a sphere See figure 1.

Figure 1 3.2.2 global linear size value of the intrinsic characteristic of a feature associated with the extracted feature NOTE 1 Several criteria may be used for this operation of association - see what follows - and different results are obtained according to the choosen criterion.

The several criteria described in this standard are: least squares, maximum inscribed, minimum circumscribed.

NOTE 2

In the following , « global linear size » is referred to only as « global size ».

3.2.2.1 least squares size value of the intrinsic characteristic of the feature associated to the extracted feature with the least squares criterion See figure 2.

Least Square Size

Figure 2 — Example of a least squares size of a cylinder

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3.2.2.2 maximum inscribed size value of the intrinsic characteristic of the feature associated to the extracted feature, with the maximum intrinsic characteristic criterion NOTE 1 For an internal feature of size, the extracted feature is outside of the associated feature (see figure 3).

NOTE 2 For an external feature of size, the extracted feature is inside of the associated feature (see figure 4).

NOTE 3 In the case of an internal feature of size, the maximum inscribed size was previously called « mating size for an internal feature ».

Max inscribed Size (d Max)

Figure 3 — Maximum inscribed size of an internal feature of size

Max inscribed Size (d Max)

Figure 4 — Maximum inscribed size of an external feature of size 3.2.2.3 minimum circumscribed size value of the intrinsic characteristic of the feature associated to the extracted feature, with the minimum intrinsic characteristic criterion NOTE 1 For an internal feature of size, the extracted feature is inside of the associated feature (see figure 5).

NOTE 2 For an external feature of size, the extracted feature is outside of the associated feature (see figure 6).

NOTE 3 In the case of an external feature of size, the minimum circumscribed size was previously called « mating size for an external feature ».

Min circumscribed Size (d min)

Figure 5 — Minimum circumscribed size of an internal feature of size

Min circumscribed Size (d min)

Figure 6 — Minimum circumscribed size of an external feature of size 3.2.3 calculation size size obtained by utilising a mathematical formula that relates the intrinsic characteristic of a feature to an other dimension(s) of the same feature

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3.2.3.1 circumference diameter size (of an extracted cylinder) calculation size, giving the diameter, d, obtained by dividing the length of the integral extracted line, L, in a cross section, normal to the axis of the associated cylinder, by pi (π π)

d=

L π

NOTE Several criteria may be used for this operation of association, and different results are obtained according to the choosen criterion.

3.2.3.2 area diameter size (of an extracted cylinder) calculation size, giving the diameter, d, obtained from the value of an area, S, limited by the integral extracted line of a cross section, normal to the axis of the associated cylinder, by the square root of four times this value divided by pi (π π)

d=

4S π

NOTE Several criteria may be used for this operation of association, and different results are obtained according to the choosen criterion.

3.2.4 statistical size size obtained from an homogeneous set of local or calculation sizes using statistical tools Envelope requirement : requirement for a feature of size defining a geometrical feature on the same type and of perfect form, at the maximum material condition, which limit the size of the extracted feature.

3.3 envelope requirement requirement for a feature of size defining a geometrical feature of the same type and of perfect form, at the maximum material condition, which limits the size of the extracted feature.

4 Symbols For the purpose of this International Standard, the following symbols apply.

Table 1 — Symbols Types of size Two-point size Local size defined by a sphere Least squares size Maximum inscribed size Minimum circumscribed size Circumference diameter size Area diameter size Minimum statistical size Maximum statistical size Average statistical size

Symbol LP LS GG GX GN CC CA SN SX SA

5 Default definition of size The default definition of size is two-point size.

Unless otherwise specified, the least square criterion is applied as a default rule when an operation of association is needed.

+ and / or – and ISO tolerance code (given in ISO 286) indications for limits of size have the same meaning (see figure 7).

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ISO/CD 14405 20

0 -0,019

20 h6

Figure 7 — Two different indications with the same meaning

6 Limits of size Unless otherwise specified, the limits of size of a feature are given by the maximum and minimum specified values. Limits of size of a feature correspond to the permissible limit deviations given by the specification by dimension.

7 Drawing indications for special definitions (non default definition) 7.1 General When the default definition does not correspond to the functional requirement, the drawing shall indicate which definition of size(s) applies : 

either an alternative default definition (different from clause 5) for all the sizes on the drawing by a general indication (for the set of characteristics with non specific indications),  or an individual special definition by an indication for each size.

In this case, modifiers are used. They are constituted by a circle including the symbol defined in Table 1.

7.2 Alternative default definition for the entire drawing The following indication :  the reference of this standard , i.e : « ISO 14405 »,  the list of the choosen definition by the corresponding modifiers given in clause 8 (including the symbols), shall be given in or near the title block.

7.3 Individual special definition 7.3.1 General When for an individual special size of a feature of size, the default definitions (either according to clause 5 or according to 7.2) do not apply, the corresponding modifier(s) shall be indicated on the dimension line, after the + and/or – indication, or after the ISO code indication.

20 h6 GG

20

0 -0,019

GG

Figure 8 — Example of indication an individual special definition of least square size 7.3.2 Use of multiple modifiers It is possible to specify limits of size of a feature, by indicating several modifiers for the same size indication.

A local size and an global size can be specified simultaneously on the same characteristic : that is equivalent to control the maximum form deviation in the same time of the limits of size.

NOTE

In the case of the circumference diameter size (see clause 5) the choosen criterion shall be defined either by GX or

by GN unless the least square criterion applies.

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8 Writing are reading rules 8.1 Writing rules 8.1.1 Local size and maximum inscribed size 8.1.1.1 If the limits of size shall be controlled by the two-point size and by the value of the intrinsic characteristic of the feature associated with the maximum inscribed characteristic criterion, then the modifiers LP and GX shall be indicated simultaneously on the same dimension line after the ± or the ISO code.

8.1.1.2 If the limits of size shall be controlled by the local size defined by a sphere and by the value of the intrinsic characteristic of the feature associated with the maximum inscribed characteristic criterion, then the modifiers

LS

and

GX

shall be indicated simultaneously on the same dimension line after the ± or the ISO code.

NOTE For an internal feature of size the indications given either in subclause 8.1.1.1 or in 8.1.1.2 are equivalent to specify the envelope requirement (see clause 9).

8.1.2 Local size and minimum circumscribed size 8.1.2.1 If the limits of size shall be controlled by the two-point size and by the value of the intrinsic characteristic of the feature associated with the minimum circumscribed characteristic criterion, then the modifiers LP and GN shall be indicated simultaneously on the same dimension line after the ± or the ISO code.

8.1.2.2 If the limits of size shall be controlled by the local size defined by a sphere and by the value of the intrinsic characteristic of the feature associated with the minimum circumscribed characteristic criterion, then the modifiers

LS

and GN shall be indicated simultaneously on the same dimension line after the ± or the ISO code.

NOTE For an external feature of size the indications given either in subclause 8.1.2.1 or in 8.1.2.2 are equivalent to specify the envelope requirement (see clause 9).

8.1.3 Local size and least squares size 8.1.3.1 If the limits of size shall be controlled by the two-point size and by the value of the intrinsic characteristic of the feature associated with the least square characteristic criterion, then the modifiers LP and GG shall be indicated simultaneously on the same dimension line after the ± or the ISO code.

8.1.3.2 If the limits of size shall be controlled by the local size defined by a sphere and by the value of the intrinsic characteristic of the feature associated with the least squares characteristic criterion, then the modifiers LS

and GG shall be indicated simultaneously on the same dimension line after the ± or the ISO code.

8.2 Reading rules 8.2.1 Local size and maximum inscribed size

LP and GX are indicated simultaneously on the same dimension line after the 8.2.1.1 If the modifiers ± or the ISO code, then the limits of size are controlled by the two-point size and by the value of the intrinsic characteristic of the associated feature. The association is based on the maximum inscribed characteristic criterion.

8.2.1.2 If the modifiers

LS and

GX are indicated simultaneously on the same dimension line after the

± or the ISO code, then the limits of size are controlled by the local size defined by a sphere and by the value of

the intrinsic characteristic of the associated feature. The association is based on the maximum inscribed characteristic criterion.

NOTE For an internal feature of size the indications given either in subclause 8.2.1.1 or in 8.2.1.2 are equivalent to specify the envelope requirement (see clause 9).

8.2.2 Local size and minimum circumscribed size

LP and GN are indicated simultaneously on the same dimension line after the 8.2.2.1 If the modifiers ± or the ISO code, then the limits of size are controlled by the two-point size and by the value of the intrinsic characteristic of the associated feature. The association is based on the minimum circumscribed characteristic criterion.

LS and GN are indicated simultaneously on the same dimension line after the 8.2.2.2 If the modifiers ± or the ISO code, then the limits of size are controlled by the local size defined by a sphere and by the value of the intrinsic characteristic of the associated feature. The association is based on the minimum circumscribed characteristic criterion.

NOTE For an external feature of size the indications given either in subclause 8.2.2.1 or in 8.2.2.2 are equivalent to specify the envelope requirement (see clause 9).

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8.2.3 Local size and least squares size

LP and GG are indicated simultaneously on the same dimension line after the 8.2.3.1 If the modifiers ± or the ISO code, then the limits of size are controlled by the two-point size and by the value of the intrinsic characteristic of the associated feature. The association is based on the least square characteristic criterion.

LS and GG are indicated simultaneously on the same dimension line after the 8.2.3.2 If the modifiers ± or the ISO code, then the limits of size are controlled by the local size defined by a sphere and by the value of the intrinsic characteristic of the associated feature . The association is based on the least squares characteristic criterion.

9 Simplifications of indications - Envelope requirement The envelope requirement can be specified on a feature of size.

This requirement means that the perfect shape corresponding to the maximum material condition shall never be overtaken.

The envelope requirement is equivalent to the local size and maximum inscribed size for an internal feature, and to the local size and minimum circumscribed size for an external feature :

E

≡ GX + LP

E

≡ GN + LP

or

or

E

≡ GX + LS

For external features

E

≡ GN + LS

For internal features

NOTE 1 Envelope requirement E has the same effect on functional requirement of a workpiece as given in ISO 8015:1985.

NOTE 2

Envelope requirement E was called « Taylor principle » in ISO 286:1988 and in ISO/R 1938:1971.

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Figure A.1

8 Local size defined by a sphere of an extracted cylinder

Local size defined by a sphere

Maximum size

Statistical size

Two points size of two parallel extracted surfaces

Minimum size

Two points size of an extracted cylinder

Two points size

Local size

Circumference diameter size

Average size

Local size defined by a sphere of two parallel extracted surfaces

Area diameter size

Calculation size

Size

Least squares size

Minimum Maximum circumscribed inscribed size size

Global size

ISO/CD 14405 Š

Annex A (informative)

Concept diagram

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Annex B (informative) Former Practice

According to ISO 286-1 :1988 clause 5.3.2 : For drawings which do not have the notation "Tolerancing ISO 8015" the default case for tolerances of the ISO system of limits and fits is the type "Two point size and mating size".

That means that form were controlled by the indication of size.

This has been changed with this standard into the default rule : The default definition of size is two-point size.

That means that form is not controlled by indication of size.

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Annex C (informative) Relation to the GPS matrix model

For full details about the GPS matrix model see ISO/TR 14638.

C.1 Information about the standard and its use [TO BE FINALIZED]

C.2 Position in the GPS matrix model This International standard is a general GPS standard, which influences the chain link 1, 2 and 3 of the chain of standards on size in the general GPS matrix, as graphically illustrated on figure C.1.

Global GPS standards General GPS matrix Chain link number

Fundamental GPS Standards

1

Size Distance Radius Angle Form of line independent of datum Form of line dependent of datum Form of surface independent of datum Form of surface dependent of datum Orientation Location Circular run-out Total run-out Datum Roughness profile Waviness profile Primary profile Surface imperfections Edges Figure C.1

C.3 Related standards The related standards are those of the chains of standards indicated in figure C.1.

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Bibliography

Mathron's Size Axioms :"Image Analysis and Mathematical Morphology" ASME Y14.5.1M-1994 "Mathematical Definition of Dimensioning and Tolerancing Principles"

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