ISO 2971:1998

Cigarettes and filter rods — Determination of nominal diameter — Method using a laser beam measuring apparatus

Cigarettes et bâtonnets-filtres — Détermination du diamètre nominal — Méthode utilisant un instrument de mesure à faisceau laser

Cigarete in filtri - Določevanje nominalnega diametra - Metoda uporabe merilnih naprav z lasarskim žarkom

General Information

• Status: Withdrawn
• Publication Date: 29-Jul-1998
• Withdrawal Date: 29-Jul-1998
• ICS: 65.160 - Tobacco, tobacco products and related equipment
• Technical Committee: ISO/TC 126/SC 1 - Physical and dimensional tests
• Drafting Committee: ISO/TC 126/SC 1 - Physical and dimensional tests
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 05-Apr-2013
• Ref Project: SIST ISO 2971:1998 - Cigarettes and filter rods -- Determination of nominal diameter -- Method using a laser beam measuring apparatus

Relations

• Revised: ISO 2971:2013 - Cigarettes and filter rods — Determination of nominal diameter — Method using a non-contact optical measuring apparatus
• Effective Date: 27-Jun-2009
• Revises: ISO 2971:1987 - Cigarettes and filters — Determination of nominal diameter — Pneumatic method
• Effective Date: 15-Apr-2008
• Revised: SIST ISO 2971:1995 - Cigarettes and filters -- Determination of nominal diameter -- Pneumatic method
• Effective Date: 12-May-2008

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 2971
Third edition
1998-08-01
Cigarettes and filter rods — Determination
of nominal diameter — Method using a
laser beam measuring apparatus
Cigarettes et bâtonnets-filtres — Détermination du diamètre nominal —
Méthode utilisant un instrument de mesure à faisceau laser
A
Reference number
ISO 2971:1998(E)

---------------------- Page: 1 ----------------------
ISO 2971:1998(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.
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.
International Standard ISO 2971 was prepared by Technical Committee
ISO/TC 126, Tobacco and tobacco products, Subcommittee SC 1, Physical
and dimensional tests.
This third edition cancels and replaces the second edition (ISO 2971:1987),
which has been technically revised.
Annex A forms an integral part of this International Standard. Annexes B
and C are for information only.
©  ISO 1998
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet [e-mail]
Printed in Switzerland
ii

---------------------- Page: 2 ----------------------
©
INTERNATIONAL STANDARD  ISO ISO 2971:1998(E)
Cigarettes and filter rods — Determination of nominal diameter —
Method using a laser beam measuring apparatus
1 Scope
This International Standard specifies a non-contact, scanning laser beam method of gauging for determination of
the mean, minimum and maximum diameters and the ovality of rod-shaped objects with a circular or oval cross-
section. The method is applicable, in particular, to cigarettes and filter rods.
NOTE 1 Alternative tape gauge and pneumatic balancing orifice measurement techniques are still widely used in the
determination of nominal diameters for cigarettes and filter rods. These alternative measurement techniques are discussed in
annex C.
NOTE 2 For laboratories using the circumference value instead of the diameter, the circumference value is calculated by
multiplying the diameter by pi (π).
2 Normative reference
The following standard contains provisions which, through reference in this text, constitute provisions of this
International Standard. At the time of publication, the edition indicated was valid. All standards are subject to
revision, and parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent edition of the standard indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
ISO 3402:1991, Tobacco and tobacco products — Atmosphere for conditioning and testing.
3 Definitions
For the purposes of this International Standard, the following definitions apply.
3.1
diameter
arithmetic mean value of a minimum of n readings (n ≥ 100) performed on a test piece following the method
specified in this International Standard
NOTE  The diameter is valid as a parameter for rod-like test pieces with a nearly circular cross-section.
3.2
minimum diameter
minimum value obtained from the results of n individual readings performed on a test piece
1

---------------------- Page: 3 ----------------------
©
ISO 2971:1998(E) ISO
3.3
maximum diameter
maximum value obtained from the results of n individual readings performed on a test piece
3.4
absolute ovality
expression of the out-of-roundness of a rod-like test piece with an oval cross-section
NOTE  It can be obtained from the arithmetic difference between the maximum and minimum diameters obtained from n
individual readings.
3.5
relative ovality
ratio of the arithmetic difference between the absolute ovality and the diameter calculated from n individual readings
NOTE 1 Relative ovality is expressed as a percentage.
NOTE 2 Caution should be exercised in interpreting maximum diameters, absolute ovality and relative ovality as these can be
affected by the quality of the gum line (raised laps), generating artificially high individual diameter readings.
4 Principle
Using the appropriate device of the apparatus, the test piece is rotated around its longitudinal axis, for a half (180°)
or full (360°) rotation, with a constant angular (rotational) speed. Simultaneously, the laser beam moves, parallel to
itself, with constant speed, in a plane (called the scan path) which is perpendicular to the longitudinal axis of the test
piece.
The intersection of the scan path with the test piece is a cross-section of the test piece.
An individual reading is the measured length of the orthogonal projection of this cross-section on a plane parallel to
the axis of the test piece.
This principle is illustrated in figure 1.
5 Apparatus
5.1 Sample conditioning enclosure, capable of maintaining the conditions given in ISO 3402.
5.2 Scanning laser beam measuring apparatus, consisting of the following.
5.2.1 Scanning laser beam measuring instrument, having a resolution of at least 0,005 mm, for the
determination of the diameter of rod-like test pieces with a nearly circular cross-section.
The scanning velocity of the laser shall be such that no eccentric motion of the test piece parallel to the longitudinal
axis, within the measurement area, shall affect the accuracy of the measurement of mean diameter.
The ratio between the scanning rate of the laser beam apparatus and the rotational speed of the test piece shall be
constant and high enough to ensure that the measured diameter, as well as the minimum and maximum values,
shall be determined with sufficient accuracy, in spite of possible ovality of the test piece.
The length of the scan path shall be at least 50 % greater than the maximum diameter to be measured and the test
piece shall be scanned a minimum of 100 times by the laser beam during a half (180°) or full (360°) rotation.
5.2.2 Apparatus or fixture for rotating the test piece in the scan path of the laser beam or to rotate the scan
path of the laser around the test piece while maintaining the longitudinal axis of the test piece perpendicular to the
scan path.
2

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©
ISO ISO 2971:1998(E)
Key
1 Receiving element
2 Converging lens
3 Test piece
4 Measurement area
5 Collimator lens
6 Scanning mirror
7 to 8 Scan path
9 Scan centreline
10 Measurement line
11 Laser beam
NOTE  For a single-axis scanner, the measurement area surrounds an ideal location found at the intersection of the
measurement line and the scan centreline. Best accuracy is achieved when the test piece is within the measurement area.
Figure 1 — Diagram of a single-axis (laser scanner) gauging system
6 Sampling
Take a statistically representative sample of the population of test pieces to be characterized.
Samples shall be free of obvious visible defects which may impair measurement performance.
7 Procedure
7.1 Preparation of test pieces
Select at random, from the sample taken in accordance with clause 6, the number of test pieces required for the
test.
Condition the test pieces, prior to measurement, in a conditioning enclosure in accordance with ISO 3402.
The times required for the curing of filter rods and the duration of conditioning for both filter rods and cigarettes are
not specified in this International Standard and are to be determined by practical experience. They shall be reported
in the test report together with the results.
3

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©
ISO 2971:1998(E) ISO
7.2 Calibration
Working standards are routinely used to calibrate or check the calibration of the laser scanning system. Calibration
shall be performed with a minimum of two standards, differing in size by at least 25 % of the measurement range of
the instrument, and of dimensions known to accuracies beyond those required for measurement.
The sizes of the test pieces to be measured shall be within the range of those of the calibration standards.
NOTE 1 One intermediate standard can be used on a routine check; its diameter should be near to that of the test piece.
NOTE 2 The essential properties of calibration standards are given in annex A.
7.3 Measurement
In accordance with the manufacturer’s instructions, position the test piece within the measurement area, as close as
possible to the intersection of the scan centreline and the measurement line.
The test piece, or the scanner, shall be capable of being rotated around the rotation axis such that any eccentric
motion of the test piece, relative to the scan path, remains in parallel with the scan path and perpendicular to the
longitudinal axis of the test piece.
Adjust the instrument and/or feeding and rotational apparatus for the scan path to scan the required section of the
test piece.
Operate the apparatus in accordance with the manufacturer’s instructions and accurately record the mean,
minimum and maximum diameters.
At least 10 test pieces from one sample should normally be used to determine the mean value of the diameter for
the sample.
NOTE 1 In practice, laboratories often take a different number of measurements depending on the application of the
measurement.
NOTE 2 It is possible to have either a rotation of the laser
...

SLOVENSKI STANDARD
SIST ISO 2971:1998
01-september-1998
&LJDUHWHLQILOWUL'RORþHYDQMHQRPLQDOQHJDGLDPHWUD0HWRGDXSRUDEHPHULOQLK
QDSUDY]ODVDUVNLPåDUNRP
Cigarettes and filter rods -- Determination of nominal diameter -- Method using a laser
beam measuring apparatus
Cigarettes et bâtonnets-filtres -- Détermination du diamètre nominal -- Méthode utilisant
un instrument de mesure à faisceau laser
Ta slovenski standard je istoveten z: ISO 2971:1998
ICS:
65.160 7REDNWREDþQLL]GHONLLQ Tobacco, tobacco products
RSUHPD and related equipment
SIST ISO 2971:1998 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

SIST ISO 2971:1998

---------------------- Page: 2 ----------------------

SIST ISO 2971:1998
INTERNATIONAL ISO
STANDARD 2971
Third edition
1998-08-01
Cigarettes and filter rods — Determination
of nominal diameter — Method using a
laser beam measuring apparatus
Cigarettes et bâtonnets-filtres — Détermination du diamètre nominal —
Méthode utilisant un instrument de mesure à faisceau laser
A
Reference number
ISO 2971:1998(E)

---------------------- Page: 3 ----------------------

SIST ISO 2971:1998
ISO 2971:1998(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.
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.
International Standard ISO 2971 was prepared by Technical Committee
ISO/TC 126, Tobacco and tobacco products, Subcommittee SC 1, Physical
and dimensional tests.
This third edition cancels and replaces the second edition (ISO 2971:1987),
which has been technically revised.
Annex A forms an integral part of this International Standard. Annexes B
and C are for information only.
©  ISO 1998
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet [e-mail]
Printed in Switzerland
ii

---------------------- Page: 4 ----------------------

SIST ISO 2971:1998
©
INTERNATIONAL STANDARD  ISO ISO 2971:1998(E)
Cigarettes and filter rods — Determination of nominal diameter —
Method using a laser beam measuring apparatus
1 Scope
This International Standard specifies a non-contact, scanning laser beam method of gauging for determination of
the mean, minimum and maximum diameters and the ovality of rod-shaped objects with a circular or oval cross-
section. The method is applicable, in particular, to cigarettes and filter rods.
NOTE 1 Alternative tape gauge and pneumatic balancing orifice measurement techniques are still widely used in the
determination of nominal diameters for cigarettes and filter rods. These alternative measurement techniques are discussed in
annex C.
NOTE 2 For laboratories using the circumference value instead of the diameter, the circumference value is calculated by
multiplying the diameter by pi (π).
2 Normative reference
The following standard contains provisions which, through reference in this text, constitute provisions of this
International Standard. At the time of publication, the edition indicated was valid. All standards are subject to
revision, and parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent edition of the standard indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
ISO 3402:1991, Tobacco and tobacco products — Atmosphere for conditioning and testing.
3 Definitions
For the purposes of this International Standard, the following definitions apply.
3.1
diameter
arithmetic mean value of a minimum of n readings (n ≥ 100) performed on a test piece following the method
specified in this International Standard
NOTE  The diameter is valid as a parameter for rod-like test pieces with a nearly circular cross-section.
3.2
minimum diameter
minimum value obtained from the results of n individual readings performed on a test piece
1

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SIST ISO 2971:1998
©
ISO 2971:1998(E) ISO
3.3
maximum diameter
maximum value obtained from the results of n individual readings performed on a test piece
3.4
absolute ovality
expression of the out-of-roundness of a rod-like test piece with an oval cross-section
NOTE  It can be obtained from the arithmetic difference between the maximum and minimum diameters obtained from n
individual readings.
3.5
relative ovality
ratio of the arithmetic difference between the absolute ovality and the diameter calculated from n individual readings
NOTE 1 Relative ovality is expressed as a percentage.
NOTE 2 Caution should be exercised in interpreting maximum diameters, absolute ovality and relative ovality as these can be
affected by the quality of the gum line (raised laps), generating artificially high individual diameter readings.
4 Principle
Using the appropriate device of the apparatus, the test piece is rotated around its longitudinal axis, for a half (180°)
or full (360°) rotation, with a constant angular (rotational) speed. Simultaneously, the laser beam moves, parallel to
itself, with constant speed, in a plane (called the scan path) which is perpendicular to the longitudinal axis of the test
piece.
The intersection of the scan path with the test piece is a cross-section of the test piece.
An individual reading is the measured length of the orthogonal projection of this cross-section on a plane parallel to
the axis of the test piece.
This principle is illustrated in figure 1.
5 Apparatus
5.1 Sample conditioning enclosure, capable of maintaining the conditions given in ISO 3402.
5.2 Scanning laser beam measuring apparatus, consisting of the following.
5.2.1 Scanning laser beam measuring instrument, having a resolution of at least 0,005 mm, for the
determination of the diameter of rod-like test pieces with a nearly circular cross-section.
The scanning velocity of the laser shall be such that no eccentric motion of the test piece parallel to the longitudinal
axis, within the measurement area, shall affect the accuracy of the measurement of mean diameter.
The ratio between the scanning rate of the laser beam apparatus and the rotational speed of the test piece shall be
constant and high enough to ensure that the measured diameter, as well as the minimum and maximum values,
shall be determined with sufficient accuracy, in spite of possible ovality of the test piece.
The length of the scan path shall be at least 50 % greater than the maximum diameter to be measured and the test
piece shall be scanned a minimum of 100 times by the laser beam during a half (180°) or full (360°) rotation.
5.2.2 Apparatus or fixture for rotating the test piece in the scan path of the laser beam or to rotate the scan
path of the laser around the test piece while maintaining the longitudinal axis of the test piece perpendicular to the
scan path.
2

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SIST ISO 2971:1998
©
ISO ISO 2971:1998(E)
Key
1 Receiving element
2 Converging lens
3 Test piece
4 Measurement area
5 Collimator lens
6 Scanning mirror
7 to 8 Scan path
9 Scan centreline
10 Measurement line
11 Laser beam
NOTE  For a single-axis scanner, the measurement area surrounds an ideal location found at the intersection of the
measurement line and the scan centreline. Best accuracy is achieved when the test piece is within the measurement area.
Figure 1 — Diagram of a single-axis (laser scanner) gauging system
6 Sampling
Take a statistically representative sample of the population of test pieces to be characterized.
Samples shall be free of obvious visible defects which may impair measurement performance.
7 Procedure
7.1 Preparation of test pieces
Select at random, from the sample taken in accordance with clause 6, the number of test pieces required for the
test.
Condition the test pieces, prior to measurement, in a conditioning enclosure in accordance with ISO 3402.
The times required for the curing of filter rods and the duration of conditioning for both filter rods and cigarettes are
not specified in this International Standard and are to be determined by practical experience. They shall be reported
in the test report together with the results.
3

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SIST ISO 2971:1998
©
ISO 2971:1998(E) ISO
7.2 Calibration
Working standards are routinely used to calibrate or check the calibration of the laser scanning system. Calibration
shall be performed with a minimum of two standards, differing in size by at least 25 % of the measurement range of
the instrument, and of dimensions known to accuracies beyond those required for measurement.
The sizes of the test pieces to be measured shall be within the range of those of the calibration standards.
NOTE 1 One intermediate standard can be used on a routine check; its diameter should be near to that of the test piece.
NOTE 2 The essential properties of calibration standards are given in annex A.
7.3 Measurement
In accordance with the manufacturer’s instructions, position the test piece within the measurement area, as close as
possible to the intersection of the scan centreline and the measurement line.
The test piece, or the scanner, shall be capable of being rotated around the rotation axis such that any eccentric
motion of the test piece, relative to the scan path, remains in parallel with the scan path and perpendicular to the
longitudinal axis of the test piece.
Adjust the instrument and/or feeding and rotation
...

NORME ISO
INTERNATIONALE 2971
Troisième édition
1998-08-01
Cigarettes et bâtonnets-filtres —
Détermination du diamètre nominal —
Méthode utilisant un instrument de mesure
à faisceau laser
Cigarettes and filter rods — Determination of nominal diameter — Method
using a laser beam measuring apparatus
A
Numéro de référence
ISO 2971:1998(F)

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ISO 2971:1998(F)
Avant-propos
L'ISO (Organisation internationale de normalisation) est une fédération
mondiale d'organismes nationaux de normalisation (comités membres de
l'ISO). L'élaboration des Normes internationales est en général confiée aux
comités techniques de l'ISO. Chaque comité membre intéressé par une
étude a le droit de faire partie du comité technique créé à cet effet. Les
organisations internationales, gouvernementales et non gouvernementales,
en liaison avec l'ISO participent également aux travaux. L'ISO collabore
étroitement avec la Commission électrotechnique internationale (CEI) en
ce qui concerne la normalisation électrotechnique.
Les projets de Normes internationales adoptés par les comités techniques
sont soumis aux comités membres pour vote. Leur publication comme
Normes internationales requiert l'approbation de 75 % au moins des
comités membres votants.
La Norme internationale ISO 2971 a été élaborée par le comité technique
ISO/TC 126, Tabac et produits du tabac, sous-comité SC 1, Essais
physiques et dimensionnels.
Cette troisième édition annule et remplace la deuxième édition
(ISO 2971:1987), dont elle constitue une révision technique.
L’annexe A fait partie intégrante de la présente Norme internationale. Les
annexes B et C sont données uniquement à titre d’information.
©  ISO 1998
Droits de reproduction réservés. Sauf prescription différente, aucune partie de cette publi-
cation ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun pro-
cédé, électronique ou mécanique, y compris la photocopie et les microfilms, sans l'accord
écrit de l'éditeur.
Organisation internationale de normalisation
Case postale 56 • CH-1211 Genève 20 • Suisse
Internet [e-mail]
Imprimé en Suisse
ii

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NORME INTERNATIONALE  © ISO ISO 2971:1998(F)
Cigarettes et bâtonnets-filtres — Détermination du diamètre
nominal — Méthode utilisant un instrument de mesure à faisceau
laser
1 Domaine d’application
La présente Norme internationale spécifie une méthode de détermination des diamètres moyen, minimal et maximal
et de l'ovalisation des objets cylindriques de section droite circulaire ou ovale par calibrage sans contact au moyen
d'un faisceau laser. La méthode est applicable en particulier aux cigarettes et aux bâtonnets-filtres.
NOTE 1 La détermination du diamètre nominal des cigarettes et bâtonnets-filtres s'effectue encore couramment par des
techniques de mesurage utilisant des rubans mesureurs ou un circuit pneumatique à pont de mesurage. Ces variantes de
technique sont décrites à l'annexe C.
NOTE 2 Les laboratoires utilisant la valeur de circonférence au lieu du diamètre peuvent la calculer en multipliant le
diamètre par pi (π).
2 Référence normative
La norme suivante contient des dispositions qui, par suite de la référence qui en est faite, constituent des
dispositions valables pour la présente Norme internationale. Au moment de la publication, l'édition indiquée était en
vigueur. Toute norme est sujette à révision et les parties prenantes des accords fondés sur la présente Norme
internationale sont invitées à rechercher la possibilité d'appliquer l'édition la plus récente de la norme indiquée ci-
après. Les membres de la CEI et de l'ISO possèdent le registre des Normes internationales en vigueur à un
moment donné.
ISO 3402:1991, Tabac et produits du tabac — Atmosphère de conditionnement et d'essai.
3 Définitions
Pour les besoins de la présente Norme internationale, les définitions suivantes s'appliquent.
3.1
diamètre
moyenne arithmétique des résultats de n lectures (n ≥ 100) effectuées sur une éprouvette en suivant la méthode
spécifiée dans la présente Norme internationale
NOTE Le diamètre est un paramètre caractérisant les éprouvettes cylindriques de section droite approximativement
circulaire.
3.2
diamètre minimal
valeur minimale des résultats obtenus sur les n lectures individuelles, effectuées sur une éprouvette
3.3
diamètre maximal
valeur maximale des résultats obtenus sur les n lectures individuelles, effectuées sur une éprouvette
1

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© ISO
ISO 2971:1998(F)
3.4
ovalisation absolue
expression de l'écart de circularité de forme d'une éprouvette cylindrique de section droite ovale
NOTE L'ovalisation peut être obtenue à partir de la différence arithmétique entre les diamètres maximal et minimal obtenus
sur les n lectures individuelles.
3.5
ovalisation relative
quotient de l'ovalisation absolue et du diamètre calculé à partir des n lectures individuelles
NOTE 1 L'ovalisation relative est exprimée en pourcentage.
NOTE 2 Il convient d'interpréter avec précaution les valeurs de diamètre maximal, d'ovalisation absolue et d'ovalisation
relative, car elles peuvent être affectées par la qualité de la couture (surépaisseur de chevauchement) qui augmente de façon
artificielle les valeurs de diamètre relevées.
4 Principe
À l'aide du dispositif de l'appareil prévu à cet effet, l'éprouvette est mise en rotation à vitesse angulaire constante
autour de son axe longitudinal, en réalisant une demi-rotation (180°) ou une rotation complète (360°). Dans le
même temps, le faisceau laser se déplace parallèlement à lui-même à vitesse constante dans un plan (appelé plan
de balayage) perpendiculaire à l'axe longitudinal de l'éprouvette.
Le plan de balayage coupe l'éprouvette selon une section droite.
Une lecture individuelle est la longueur de la projection orthogonale de cette section droite sur un plan parallèle à
l'axe de l'éprouvette.
Le principe est illustré à la figure 1.
5 Appareillage
5.1  Enceinte de conditionnement de l'échantillon, capable de maintenir les conditions données dans
l'ISO 3402.
5.2  Appareil de mesurage à balayage par faisceau laser, constitué des éléments suivants.
5.2.1  Instrument de mesurage à faisceau laser, ayant une résolution d'au moins 0,005 mm, pour la
détermination du diamètre d'éprouvettes cylindriques de section droite approximativement circulaire.
La vitesse de balayage du laser doit être telle qu'à l'intérieur de la zone de mesurage aucun mouvement
excentrique de l'éprouvette parallèlement à l'axe longitudinal n'affecte la précision de la mesure du diamètre moyen.
Le rapport de la vitesse de balayage de l'instrument à faisceau laser à la vitesse de rotation de l'éprouvette doit être
constant et suffisamment grand pour permettre de déterminer avec une précision suffisante non seulement le
diamètre mesuré mais aussi les valeurs minimale et maximale de diamètres variant en continu.
La longueur de la trajectoire de balayage doit être supérieure d'au moins 50 % au diamètre maximal à mesurer et
l'éprouvette doit être explorée au minimum 100 fois par le faisceau laser au cours d'une demi-rotation (180°) ou
d'une rotation complète (360°).
5.2.2  Appareil ou montage permettant de faire tourner l'éprouvette dans la trajectoire du faisceau laser ou de
faire tourner le faisceau laser autour de l'éprouvette tout en maintenant l'axe longitudinal de l'éprouvette
perpendiculaire à la trajectoire de balayage.
2

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© ISO
ISO 2971:1998(F)
Légende
1 Élément récepteur
2 Lentille convergente
3 Éprouvette
4 Zone de mesurage
5 Lentille de collimateur
6 Miroir
7 à 8 Trajectoire de balayage
9 Axe de balayage
10 Axe de mesurage
11 Faisceau laser
NOTE Lorsque le balayage est uniaxial, la zone de mesurage entoure un lieu idéal qui se trouve à l'intersection de l'axe de
mesurage et de l'axe de balayage. La précision de mesurage est optimale lorsque l'éprouvette reste fixe dans cette zone.
Figure 1 — Schéma d'un système de calibrage uniaxial (balayage laser)
6 Échantillonnage
Prélever un échantillon représentatif sur le plan statistique de la population d'éprouvettes à caractériser.
Les échantillons doivent être exempts de défauts visibles évidents pouvant compromettre la performance de
mesurage.
7 Mode opératoire
7.1 Préparation des éprouvettes
Sur l'échantillon sélectionné conformément à l'article 6, prélever au hasard le nombre d'éprouvettes requis pour
l'essai.
Conditionner les éprouvettes avant le mesurage dans une enceinte de conditionnement conformément à
l'ISO 3402.
Le temps de séchage des bâtonnets-filtres et le temps de conditionnement des cigarettes et des bâtonnets-filtres
ne sont pas spécifiés dans la présente Norme internationale et sont déterminés par l'expérience pratique acquise.
Ils doivent être consignés dans le rapport d'essai avec les résultats.
3

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© ISO
ISO 2971:1998(F)
7.2 Étalonnage
Des piges de travail sont communément utilisées pour l'étalonnage ou la vérification de l'étalonnage de l'appareil à
faisceau laser. Ce dernier doit être étalonné avec un minimum de deux piges dont les diamètres diffèrent d'au
moins 25 % de l'étendue de mesurage de l'appareil et dont les dimensions sont connues avec une précision
supérieure à celle requise pour le mesurage.
Le diamètre des éprouvettes pour essai doit se situer à l'intérieur de la plage dimensionnelle des piges étalons.
NOTE 1 En contrôle de routine, il est admis d'utiliser une seule pige intermédiaire de diamètre proche de celui de
l'éprouvette.
NOTE 2 Les propriétés essentielles des piges étalons sont données à l’annexe A.
7.3 Mesurage
Conformément aux instructions du fabricant, placer l'éprouvette à l'intérieur de la zone de mesurage, aussi près que
possible de l'intersection entre l'axe de balayage et l'axe de mesurage.
Faire tourner l'éprouvette ou l'appareil à faisceau laser autour de l'axe de rotation de telle sorte que tout mouvement
excentrique de l'éprouvette par rapport à la trajectoire de balayage soit parallèle à ce dernier tout en restant
perpendiculaire à l'axe longitudinal de l'éprouvette.
Régler l'instrument et/ou le dispositif d'avance ou de rotation de manière à explorer la section requise de
l'éprouvette.
Faire fonctionner l'appareil selon les instructions du fabricant et enregistrer avec précision les diamètres moyen,
minimal et maximal.
Il convient normalement d'utiliser au moins 10 éprouvettes d'un même échantillon pour déterminer la valeur
moyenne du diamètre de l'échantilllon.
NOTE 1 Dans la pratique, les laboratoires utilisent souvent un nombre de mesures différent dépendant de l'application du
mesurage.
NOTE 2 Il est possible de procéder soit par rotation du faisceau laser autour de l'objet soit par rotation de l'objet dans le
faisceau laser.
NOTE 3 L
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