NES-D0096 2006-1 Geometrical Tolerancing - Positinal Tolerancing

7/27/2019 NES-D0096 2006-1 Geometrical Tolerancing - Positinal Tolerancing

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Nissan Engineering Standard

N E S Geometrical tolerancing Positional Tolerancing

IntroductionThis Standard has been prepared as a translation of ISO 5458 issued in 1998 without changing the tech-nical details and it is established as NES according to the current format. However, the title of this Standardis Geometrical tolerancing - Positional tolerancing and the details of the Standard has been partiallychanged in accordance with conditions at Nissan.

1. SCOPE

This Standard describes positional tolerancing. This tolerancing method is applied to the location of a point,

of a line nominally straight or and of a surface nominally plane.

Profile tolerancing is used when lines are not intended to be straight of surfaces are not intended to lie in a

plane; see NES D0401:2006-N/ISO 1660:1987.

2. ESTABLISHMENT OF POSITIONAL TOLERANCES

2.1 General

The primary constituents are theoretically exact dimensions, tolerance zones and datums.

2.2 Fundamental requirement

Positional tolerances are associated with theoretically exact dimensions and define the limits for the loca-

tion of actual features, such as points, axes, median surfaces, nominally straight lines and nominally

plane surface relative to each other or in relation to one or more datumes. The tolerance zone is symmet-

rically disposed about theoretically exact location.

Remark: Positional tolerances do not accumulate when theoretically exact dimension are arranged in a chain (see Figure 4). (This

contrasts with dimensional tolerances that are arranged in a chain.) Positional tolerancing allows clear reference to be

made to one or more datums.

Normative References and References: See page 8.


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2.3 Theoretically exact dimensions

Theoretically exact dimensions, both angular and linear, are indicated by being enclosed in a rectangular

frame in accordance with NES D0097:2004-N/ISO 1101:1983. This is illustrated in figures 2a), 2b), 3a),

4a), 5a), and 7a).

The theoretically exact dimensions 0and 90, 180or distance 0 between

- positionally toleranced features not related to a datum [See Figure 4a) and Figure 5a).]

- positionally toleranced features related to the same datum(s) [See Figure 2a).]

- positionally toleranced features and their related datums (See Figure 1.)

are implied without specific indication.

When the positional tolerance features share the same centerline or axis, they are regarded as theoreti-

cally exact related features, unless otherwise specified, e.g. in relation to different data or other reason in-

dicated by an appropriate note on the drawing as shown in Figure 2b).

Indication on the drawing Explanation

Figure 1Case a), b), c) or d) may apply at each individualhole:

a) axis of hole coincident with the theoretically exactlocation (zero deviation);

b) axis of hole at maximum position deviation withzero perpendicularity deviation;

c) axis of hole at maximum position deviation withmaximum perpendicularity deviation;

d) axis of hole at maximum position deviation; in thiscase a combination of geometrical deviations.


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2.4 Positional tolerance on a complete circle

When positionally toleranced features are arranged in a circle it is understood that the features are

equally spaced, unless otherwise stated, and that their locations are theoretically exact.

If two or more groups of features are shown on the same axis, they shall be considered to be a single

pattern when:

- they are not related to a datum;

- they are related to the same datum or datum system (datum in the same order of precedence or under

the same material conditions) [See Figure 2a)].

unless otherwise stated [See Figure 2b)].

Figure 2a)

Figure 2b)

Angular location optional


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2.5 Directions of positional tolerances

2.5.1 Positional tolerances in one direction onlyThe tolerance value can be specified in one direction. The orientation of the width of the tolerance zone

is based on pattern of theoretically exact dimensions and is at 0o

or 90o

as indicated by the direction of

the arrow line [See Figures 3a) and 3b).] unless otherwise indicated.

Figure 3a) Indication on the drawing

Figure 3b) Explanation

Key

1 Simulated datum A

2 Simulated datum B

Each of the scale lines shall be contained within a tolerance zone defined by two parallel straight lines 0.1

apart which are symmetrical disposed about the theoretically exact position of each scale line relative to

each other.


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2.5.2 Positional tolerances in two directions

The tolerance value can be specified in two directions perpendicular to each other, reference being

made to unequal values [see Figures 4a) and 4b)] or equal values.

Figure 4a) Indication of the drawing

Figure 4b) Explanation

Each hole shall be:

- measured in the direction of the theoretically exact dimension 30; its actual median surface lies within a

tolerance zone with a rectangular cross-section of 0.3 x 7 mm (actual length of the feature);

- measured in the direction of the theoretically exact dimension 28; its actual median surface lies within a

tolerance zone with a rectangular cross-section of 0.1 x 7 mm (actual length of the feature);

- the median planes of the tolerance zones are fixed by the theoretically exact dimensions.


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2.5.3 Multi-directional positional tolerances

The tolerance is specified as a cylindrical tolerance zone [see figures 5a) and 5b)].


Figure 5b) Interpretation

The actual axis of each hole shall be lie within a cylindrical tolerance zone of diameter 0.1 mm; the axes of

the cylindrical tolerances zones are fixed by theoretically exact dimensions.

Note For cylindrical features of mating parts, the tolerance zone is usually cylindrical, as the positional tolerance is multi-directional

from the theoretically exact location. In these cases the positional tolerancing method achieves a larger tolerance zone than in

the two directions method which can only generate a square (or rectangular) two dimensional tolerance zone (See Figure 6.).

The choice between multi-directional and two directions tolerance zone should be made according to the function of the tol-

eranced feature.

Key:

1. 57% larger tolerance zone

Figure 6

1


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3. TOLERANCE COMBINATIONS

3.1 If a group of features is individually located by positional tolerancing and their pattern location is also lo-

cated by positional tolerancing, each requirement shall be met independently [See Figure 7a)].

3.2 The actual axis of each of the four holes shall lie within the cylindrical tolerance zone of diameter 0.01. In

addition, the positional tolerance zones are located in their theoretically exact positions to each other and

perpendicular to datum A [See Figure 7b)].

3.3 The actual axis of each holes shall lie within the cylindrical tolerance zone of diameter 0.2; the positional

tolerance zones are perpendicular to datum A and located in their exact theoretical positions in relation to

each other and to the datums B and C [see figure 7c)].


1 Simulated datum A 1 Simulated datum A2 Simulated datum B3 Simulated datum C

Figure 7b) Explanation Figure 7c) Explanation


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Normative References: NES D0097:2004-N Geometrical tolerancing Tolerancing of form, orienta-

tion, location and run-out

NES D0401:2006-N Dimensionings and tolerancing of profiles

References:

ISO 1101:1983 Geometrical Product Specifications (GPS) Generalities, definitions, sym-

bols, indications on drawings

For the above ISO, the following is the latest as of March 2006.

ISO 1101:2004 Geometrical Product Specifications (GPS) Geometrical tolerancing

Tolerances of form, orientation, location and run-out

ISO 1660:1987 Technical drawings Dimensioning and tolerancing of profiles

ISO 2692:1998 Technical drawings Geometrical tolerancing Maximum material principle

ISO 3098-1:1974 Technical drawings Lettering Parts 1: Latin alphabet, numerals and

marks


ISO 3098-2:2000 Technical product documentation -- Lettering

Part 2: Latin alphabet, numerals and marks

ISO 5459:1981 Technical drawings Geometrical tolerancing Datums and datum-systems

for geometrical tolerances

ISO/TR 14638:1995 Geometrical product specifications (GPS) Masterplan

ISO 14660-1: Geometrical product specifications (GPS) Geometric features

Parts 1: General terms and definitions


ISO 14660-1:1999 Geometrical product specifications (GPS) Geometric featurees Parts 1:

General terms and definitions


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ANNEX

1. Introduction

This Standard is the so-called translated standard ofISO 5458 (Technical drawings-Geometrical-

Positional-Tolerancing).

2. Explanations of each item2.1 Differences from ISO 5458

There is no difference of engineering contents between the text of this Standard and ISO 5458, and the

interpretation does not differ in cases where either of them is used, and also the explanation drawings are

the same.

The only change is that it was described additionally in cases where it is planned to issue the NES for each

Standard that is referred to in the text.

3. Revision in April, 2004

Figure 2a) on page 3 and Figure 6 on page 6 were out of order, therefore, they were corrected.

The contents were not changed.

4. Purpose of revision in 2005Based on the periodical revision, it was reviewed. The following two points describe the changes. No en-

gineering revision was implemented.

1. Issue years were not described for the NES/ISO standards quoted in the text, therefore, they were clari-

fied. (One place on page 1 and one place on page 2)

2. The engineering contents of this Standard are the same as those of ISO 5458:1998. Therefore, as the

References, those for this ISO Standard and the corresponding JIS B0025:1998 are listed as they are.

For the revised ones of these, it was described for reference that they were revised.

3. Since Normative References were revised, they were updated to the latest ones. Only typographical er-

rors and omissions were corrected, but the contents were not changed for Normative References.

Documents

NES-D0096 2006-1 Geometrical Tolerancing - Positinal Tolerancing