ISO 16945:2014

Corrugating medium — Determination of the edge crush resistance after laboratory fluting

ISO 16945:2014 specifies two methods for the determination of the edge crush resistance of a corrugating medium after laboratory fluting. The procedures are applicable to any corrugating medium to be used after fluting in the manufacture of corrugated fibreboard.

Papier cannelure pour carton ondulé — Détermination de la résistance à la compression sur chant après cannelage en laboratoire

General Information

• Status: Published
• Publication Date: 20-Feb-2014
• ICS: 85.060 - Paper and board
• Technical Committee: ISO/TC 6/SC 2 - Test methods and quality specifications for paper and board
• Drafting Committee: ISO/TC 6/SC 2 - Test methods and quality specifications for paper and board
• Current Stage: 9020 - International Standard under periodical review
• Start Date: 15-Jul-2024
• Completion Date: 15-Jul-2024

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 16945
First edition
2014-03-01
Corrugating medium — Determination
of the edge crush resistance after
laboratory fluting
Papier cannelure pour carton ondulé — Détermination de la
résistance à la compression sur chant après cannelage en laboratoire
Reference number
©
ISO 2014
© ISO 2014
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2014 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 2
6 Sampling . 4
7 Conditioning . 4
8 Preparation of test pieces . 4
9 Procedure. 4
9.1 General . 4
9.2 Testing immediately after fluting . 4
9.3 Testing after 30 min of reconditioning . 4
9.4 Fluting and testing . 4
10 Calculation . 5
10.1 Edge crush resistance . 5
10.2 Edge crush resistance index . 5
11 Test report . 5
Annex A (informative) Precision . 7
Annex B (informative) Maintenance of fluting rolls (horizontal type) . 9
Bibliography .10
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 6, Paper, board and pulps, Subcommittee SC 2,
Test methods and quality specifications for paper and board.
iv © ISO 2014 – All rights reserved

Introduction
This International Standard evaluates the ability of corrugating medium to contribute to the compression
strength of a corrugated box. It is a procedure for measuring the edgewise compression strength of a
laboratory-fluted strip of corrugating medium. The corrugated medium is fluted by passing it between
heated rollers. Two different test procedures are then widely used.
a) The fluted corrugating medium is compressed immediately after fluting (i.e 20 s to 25 s after
fluting).
b) The fluted corrugating medium is conditioned for 30 min to 35 min after fluting under standard
laboratory test conditions before being compressed.
Procedure a) generally gives considerably higher results than those obtained with procedure b). The
differences in results are claimed to be caused by the lower moisture content (and thus higher stiffness)
of the unconditioned fluted corrugating medium.
Since considerable advantages are claimed for both procedures and both are widely used, this
International Standard describes both procedures.
Test values and failure modes in this approach are expected to be different than those for ring crush
method and short span compression test (SCT).
NOTE This test is sometimes referred to as CCT (corrugated crush test) or CFC (corrugated fluted crush test).
INTERNATIONAL STANDARD ISO 16945:2014(E)
Corrugating medium — Determination of the edge crush
resistance after laboratory fluting
1 Scope
This International Standard specifies two methods for the determination of the edge crush resistance
of a corrugating medium after laboratory fluting. The procedures are applicable to any corrugating
medium to be used after fluting in the manufacture of corrugated fibreboard.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 186, Paper and board — Sampling to determine average quality
ISO 187, Paper, board and pulps — Standard atmosphere for conditioning and testing and procedure for
monitoring the atmosphere and conditioning of samples
ISO 536, Paper and board — Determination of grammage
ISO 13820, Paper, board and corrugated fibreboard — Description and calibration of compression-testing
equipment
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
edge crush resistance
CCT
maximum edgewise compression force per unit length that a laboratory fluted test piece will withstand
before onset of break under the test conditions specified in this International Standard
Note 1 to entry: Edge crush resistance is expressed in kilonewtons per metre (kN/m).
3.2
edge crush resistance index
edge crush resistance divided by the grammage
Note 1 to entry: The result is expressed in newton metres per gram (Nm/g).
4 Principle
The principle is as follows:
a) fluting of the paper by passing it between heated rollers and mounting in a holder with the flutes
placed vertically;
b) application of a compressive force and determination of the maximum force per unit length.
5 Apparatus
5.1 Cutting device, for cutting the test pieces to the required specifications, see Clause 8.
5.2 Fluter, consisting of a pair of matched steel corrugating rolls. The rolls shall be capable of being
maintained at a temperature of 175 °C ± 8 °C. The temperature is controlled by any suitable method.
Check the temperature when the rolls are in motion.
One roll is motor-driven at 4,5 r/min ± 1,0 r/min and the rolls are held in mesh by a force of (100 ± 10) N
exerted between the rolls and distributed evenly across the teeth, under test conditions. In some
instruments, the force between the rolls is applied by a spring acting in a slide. In such instruments,
friction in this device can result in the force which acts upon the test piece being considerably less than
the force required to displace the rolls initially. When verifying that an instrument conforms to the
requirements given in this subclause, it is therefore necessary to measure the force required to prevent
the undriven roll from moving towards the driven roll, from a position about 200 μm away.
The essential characteristics of each roll are the following (see also Figure 1):
— roll diameter: 228,5 mm ± 0,5 mm;
— roll thickness: 16 mm ± 1 mm;
— number of teeth: 84 (see Note 3 below);
— radius of teeth at peak: 1,5 mm ± 0,1 mm;
— radius of teeth at base: 2,0 mm ± 0,1 mm;
— depth of teeth: 4,75 mm ± 0,05 mm;
— distance between teeth (peak to peak around the arc): 8,55 mm ± 0,05 mm.
In order to optimize the matching of pairs of rolls, pairs of rolls should be selected in which the differences
in dimensions between the two are substantially less than the tolerances shown. Prior to first use, the
rolls should be run at the operating temperature for about 6 h with a mild abrasive on the teeth. The two
rolls should then be marked in some way so that, after removal for cleaning or maintenance, they can be
reassembled with exactly the same teeth in mesh.
NOTE 1 It is recommended to have a guiding device to help feed the test piece perpendicular to the corrugating
nip.
[2]
NOTE 2 The fluter is identical to that used for ISO 7263 .
NOTE 3 In some fluters, a full roll is not used.
2 © ISO 2014 – All rights reserved

Dimensions in millimetres
Figure 1 — Profile of corrugating rolls
5.3 Holder, with a profile matching the profile of the corrugated medium, able to hold the test piece
so that the flutes are vertical. The holder can be opened for mounting of test pieces. A suitable stopping
surface exists so that 6,35 mm width of the specimen is grasped by the holder (see Figure 2).
The fluted crush test piece holder should conform to the same parallelism requirements as the crush
tester (see 5.4).
Dimensions in millimetres
A
B
Key
A test piece
B test piece holder
Figure 2 — Test piece holder
5.4 Compression tester, a motor-driven, fixed-platen type compression tester in accordance with
ISO 13820.
12,7
6,35
6 Sampling
If the tests are being made to evaluate a lot, the sample shall be selected in accordance with ISO 186. If
the tests are made on another type of sample, make sure that the specimens taken are representative of
the sample received.
7 Conditioning
Condition the samples in accordance with ISO 187.
8 Preparation of test pieces
Cut at least 10 test pieces in 12
...

DRAFT INTERNATIONAL STANDARD ISO/DIS 16945
ISO/TC 6/SC 2 Secretariat: SIS
Voting begins on Voting terminates on

2013-02-25 2013-05-25
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION  •  МЕЖДУНАРОДНАЯ ОРГАНИЗАЦИЯ ПО СТАНДАРТИЗАЦИИ  •  ORGANISATION INTERNATIONALE DE NORMALISATION

Corrugating medium — Determination of the edge crush
resistance after laboratory fluting
Papier cannelure pour carton ondulé — Détermination de la résistance à la compression sur chant après
cannelage en laboratoire
ICS 85.060
To expedite distribution, this document is circulated as received from the committee
secretariat. ISO Central Secretariat work of editing and text composition will be undertaken at
publication stage.
Pour accélérer la distribution, le présent document est distribué tel qu'il est parvenu du
secrétariat du comité. Le travail de rédaction et de composition de texte sera effectué au
Secrétariat central de l'ISO au stade de publication.

THIS DOCUMENT IS A DRAFT CIRCULATED FOR COMMENT AND APPROVAL. IT IS THEREFORE SUBJECT TO CHANGE AND MAY NOT BE
REFERRED TO AS AN INTERNATIONAL STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS BEING ACCEPTABLE FOR INDUSTRIAL, TECHNOLOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT, WITH THEIR COMMENTS, NOTIFICATION OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPORTING DOCUMENTATION.
©  International Organization for Standardization, 2013

ISO/DIS 16945
Copyright notice
This ISO document is a Draft International Standard and is copyright-protected by ISO. Except as permitted
under the applicable laws of the user’s country, neither this ISO draft nor any extract from it may be
reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic,
photocopying, recording or otherwise, without prior written permission being secured.
Requests for permission to reproduce should be addressed to either ISO at the address below or ISO’s
member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Reproduction may be subject to royalty payments or a licensing agreement.
Violators may be prosecuted.
ii © ISO 2013 – All rights reserved

ISO/DIS 16945
Contents Page
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle. 1
5 Apparatus . 2
5.1 Cutting device . 2
5.2 Fluter . 2
5.3 Holder . 3
5.4 Compression tester . 4
6 Sampling. 4
7 Conditioning . 4
8 Preparation of test pieces. 4
9 Procedure . 4
9.1 General . 4
9.2 Testing immediately after fluting . 4
9.3 Testing after 30 minutes of reconditioning. 4
9.4 Fluting and testing . 4
10 Calculation . 5
10.1 Edge crush resistance . 5
10.2 Edge crush resistance index . 5
11 Test report . 6
Annex A (informative) Precision . 7
Annex B (informative) Maintenance of fluting rolls (horizontal type) . 9
Bibliography . 10

ISO/DIS 16945
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 16945 was prepared by Technical Committee ISO/TC 6, Paper, board and pulps, Subcommittee SC 2,
Test methods and quality specifications for paper and board.
iv © ISO 2012 – All rights reserved

ISO/DIS 16945
Introduction
This test evaluates the ability of corrugating medium to contribute to the compression strength of a corrugated
box. It is a procedure for measuring the edgewise compression strength of a laboratory-fluted strip of
corrugating medium. The corrugated medium is fluted by passing it between heated rollers. Two different test
procedures are then widely used:
a) the fluted corrugating medium is compressed immediately after fluting (i.e 20 s to 25 s after fluting);
b) the fluted corrugating medium is conditioned for 30 min to 35 min under standard laboratory test
conditions before being compressed.
Procedure a) generally gives considerably higher results than those obtained with procedure b). The
differences in results are claimed to be caused by the lower moisture content (and thus higher stiffness) of the
unconditioned fluted corrugating medium.
Since considerable advantages are claimed for both procedures and both are widely used, this International
Standard describes both procedures.
Test values and failure modes in this approach are expected to be different than those for Ring crush method
and Short span compression test (SCT).
NOTE This test is sometimes referred to as CCT (corrugated crush test) or CFC (corrugated fluted crush test).
DRAFT INTERNATIONAL STANDARD ISO/DIS 16945

Corrugating medium — Determination of edge crush resistance
after laboratory fluting
1 Scope
This International Standard specifies two methods for the determination of the edge crush resistance of a
corrugating medium after laboratory fluting. The procedures are applicable to any corrugating medium to be
used, after fluting, in the manufacture of corrugated fibreboard.
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 186, Paper and board — Sampling to determine average quality
ISO 187, Paper, board and pulps — Standard atmosphere for conditioning and testing and procedure for
monitoring the atmosphere and conditioning of samples
ISO 536, Paper and board — Determination of grammage
ISO 13820, Paper, board and corrugated fibreboard — Description and calibration of compression-testing
equipment
3 Terms and definitions
For the purposes of this document, the following term and definition apply.
3.1
edge crush resistance
CCT
maximum edgewise compression force per unit length that a laboratory fluted test piece will withstand before
onset of break under the test conditions specified in this International Standard
NOTE Edge crush resistance is expressed in kilonewtons per metre (kN/m).
3.2
edge crush resistance index
edge crush resistance divided by the grammage
NOTE The result is expressed in newton metres per gram (Nm/g)
4 Principle
Fluting of the paper by passing it between heated rollers and mounting in a holder with the flutes placed
vertically. Application of a compressive force and determination of the maximum force per unit length.
ISO/DIS 16945
5 Apparatus
5.1 Cutting device
A cutting device for cutting the test pieces to the required specifications, see Clause 8.
5.2 Fluter
A fluter consisting of a pair of matched steel corrugating rolls. The rolls shall be capable of being maintained
at a temperature of 175 °C ± 8 °C. The temperature is controlled by any suitable method. Check the
temperature when the rolls are in motion.
One roll is motor-driven at 4,5 r/min ± 1,0 r/min and the rolls are held in mesh by a force of 100  ± 10 N
exerted between the rolls and distributed evenly across the teeth, under test conditions. In some instruments,
the force between the rolls is applied by a spring acting in a slide. In such instruments, friction in this device
can result in the force which acts upon the test piece being considerably less than the force required to
displace the rolls initially. When verifying that an instrument conforms to the requirements given in this
subclause, it is therefore necessary to measure the force required to just prevent the undriven roll from
moving towards the driven roll, from a position about 200 μm away.
The essential characteristics of each roll are the following (see also Figure 1):
Roll diameter 228,5 mm ± 0,5 mm
Roll thickness 16 mm ± 1 mm
Number of teeth 84 (see Note below)
Radius of teeth at peak 1,5 mm ± 0,1 mm
Radius of teeth at base 2,0 mm ± 0,1 mm
Depth of teeth 4,75 mm ± 0,05 mm
Distance between teeth (peak to peak around the arc) 8,55 mm ± 0,05 mm
In order to optimize the matching of pairs of rolls, pairs of rolls should be selected in which the differences in
dimensions between the two are substantially less than the tolerances shown. A difference of ± 0,1 mm or
better is recommended.
NOTE 1 It is recommended to have a guiding device to help feed the test piece perpendicular to the corrugating nip.
[2]
NOTE 2 The fluter is identical to that used for ISO 7263 .
NOTE 3 In some fluters, a full roll is not used.
2 © ISO 2012 – All rights reserved

ISO/DIS 16945
Dimensions in millimetres
Figure 1 – Profile of corrugating rolls
5.3 Holder
A holder with a profile matching the profile of the corrugated medium, able to hold the test piece so that the
flutes are vertical. The holder can be opened for mounting of test pieces. A suitable stopping surface exists so
that 6,35 mm width of the specimen is grasped by the holder. (See Figure 2.)
The fluted crush test piece holder should conform to the same parallelism requirements as the crush tester
(see 5.4).
Dimensions in millimetres
A
B
Key
A test piece
B test piece holder
Figure 2 – Test piece holder
12,7
6,35
ISO/DIS 16945
5.4 Compression tester
A motor-driven, fixed-platen type compression tester in accordance with ISO 13820.
6 Sampling
If the tests are being made to evaluate a lot, the sample shall be selected in accordance with ISO 186. If the
tests are made on another type of sample, make sure that the specimens taken are representative of the
sample received.
7 Conditioning
Condition t
...