IEC 61189-2-501:2022

IEC 61189-2-501 ®
Edition 1.0 2022-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Test methods for electrical materials, printed boards and other interconnection
structures and assemblies –
Part 2-501: Test methods for materials for interconnection structures –
Measurement of resilience strength and resilience strength retention factor of
flexible dielectric materials
Méthodes d'essai pour les matériaux électriques, les cartes imprimées et autres
structures d'interconnexion et ensembles –
Partie 2-501: Méthodes d’essai des matériaux pour structures d’interconnexion –
Mesure de la puissance élastique et du facteur de rétention de la puissance
élastique des matériaux diélectriques flexibles

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IEC 61189-2-501 ®
Edition 1.0 2022-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Test methods for electrical materials, printed boards and other interconnection

structures and assemblies –
Part 2-501: Test methods for materials for interconnection structures –

Measurement of resilience strength and resilience strength retention factor of

flexible dielectric materials
Méthodes d'essai pour les matériaux électriques, les cartes imprimées et autres

structures d'interconnexion et ensembles –

Partie 2-501: Méthodes d’essai des matériaux pour structures d’interconnexion –

Mesure de la puissance élastique et du facteur de rétention de la puissance

élastique des matériaux diélectriques flexibles

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.180 ISBN 978-2-8322-1071-7

– 2 – IEC 61189-2-501:2022  IEC 2022
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Test apparatus and materials . 8
5 Test specimens . 8
6 Procedure . 8
7 Calculation . 10
8 Report . 11
Annex A (informative) Example of test fixture . 12

Figure 1 – Test specimen . 8
Figure 2 – Schematic of compression jig with test specimen . 9
Figure 3 – Force curve . 10
Figure A.1 – A test fixture and a fixture with a sample . 12
Figure A.2 – General assembly drawing . 13
Figure A.3 – A detailed dimensional drawing for each part of an example test fixture . 15
Figure A.4 – Construction of a test fixture is using the parts shown in Figure A.3 . 16
Figure A.5 – Connector attachments . 16

Table 1 – Settings of distance between the clamps after compression . 9
Table A.1 – Parts list . 13

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
TEST METHODS FOR ELECTRICAL MATERIALS, PRINTED BOARDS
AND OTHER INTERCONNECTION STRUCTURES AND ASSEMBLIES –

Part 2-501: Test methods for materials for interconnection structures –
Measurement of resilience strength and resilience strength retention
factor of flexible dielectric materials

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
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Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC 61189-2-501 has been prepared by IEC technical committee TC 91: Electronics assembly
technology. It is an International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
91/1765/FDIS 91/1774/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.

– 4 – IEC 61189-2-501:2022  IEC 2022
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
A list of all parts in the IEC 61189 series, published under the general title Test methods for
electrical materials, printed boards and other interconnection structures and assemblies, can
be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates that it
contains colours which are considered to be useful for the correct understanding of its
contents. Users should therefore print this document using a colour printer.

INTRODUCTION
The International Electrotechnical Commission (IEC) draws attention to the fact that it is claimed
that compliance with this document may involve the use of a patent. IEC takes no position
concerning the evidence, validity, and scope of this patent right.
The holder of this patent right has assured IEC that s/he is willing to negotiate licences under
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Attention is drawn to the possibility that some of the elements of this document may be the
subject of patent rights other than those in the patent database. IEC shall not be held
responsible for identifying any or all such patent rights.

– 6 – IEC 61189-2-501:2022  IEC 2022
TEST METHODS FOR ELECTRICAL MATERIALS, PRINTED BOARDS
AND OTHER INTERCONNECTION STRUCTURES AND ASSEMBLIES –

Part 2-501: Test methods for materials for interconnection structures –
Measurement of resilience strength and resilience strength retention
factor of flexible dielectric materials

1 Scope
This part of IEC 61189 establishes a method suitable for testing the softness of FCCL (Flexible
Copper Clad Laminate) products and related materials. This method determines the resilience
under specified conditions. The test is performed on the sample as manufactured and without
conditioning. The test does not apply to the resilience force lower than 10 mN.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
softness
property of little resistance to pressure
Note 1 to entry: This property enables easy molding.
3.2
resilience force
force produced by the deformation of an object under a force, which is opposite to the direction
of the applied force
3.3
maximum resilience force
L
max
resilience force when compressed to the final distance, expressed in millinewtons (mN)
3.4
resilience strength
F
max
resilience force per unit width, expressed in millinewtons per millimetres (mN/mm)

3.5
resilience force at the end of holding pressure
L
end
resilience force after compression to the final distance and held for a specified time, expressed
in millinewtons (mN)
3.6
resilience strength at the end of holding pressure
F
end
resilience force per unit width at the end of holding pressure, expressed in millinewtons per
millimetres (mN/mm)
3.7
resilience strength retention factor
K
Rf
ratio of the resilience strength at the end of holding pressure to the maximum resilience strength
at the final distance, reflecting the ability of the material to continue to retain the resilience after
the compression is completed
3.8
MD
machine direction
direction of flexible dielectric materials passing through an assembly line viewed from the
operator side
3.9
TD
transverse direction
direction perpendicular to the machine direction
3.10
initial distance
distance between the clamps before compression, expressed in millimetres (mm)
3.11
clamp distance
distance between the clamps, expressed in millimetres (mm)
3.12
test equipment
calibrated test equipment equipped with a load cell, capable of measuring to the nearest
0,001 N, and capable of a feed rate of (50 ± 1) mm per minutes
Note 1 to entry: The clamp jaws must cover the width of specimens.
3.13
test fixture
apparatus for compressing the test specimens
SEE: Figure 2
Note 1 to entry: See Annex A for additional information.

– 8 – IEC 61189-2-501:2022  IEC 2022
4 Test apparatus and materials
The test apparatus and materials are the following:
– micrometer: apparatus with 0,001 mm resolution for measuring the thickness of the test
specimens;
– calliper: apparatus with 0,01 mm resolution for measuring the width of the test specimens;
– ruler: apparatus with 0,1 mm resolution for measuring the length of the test specimens;
– sample cutter: apparatus for cutting the test specimens;
– marking pen: apparatus for drawing a straight line on test specimens as shown in Figure 1
with a clearly readable colour, in contrast to the colour of the test specimen.
The marking should be durable through the whole test procedure.
5 Test specimens
Test specimens should be cut of unclad material. The size of each specimen should be
(120 ± 2,0) mm × (15 ± 0,1) mm, described in Figure 1. Each specimen should be marked as
described in Figure 1. The test specimen should be free of incisions, twists, wrinkles and burrs.
Dimensions in millimetres
Figure 1 – Test specimen
6 Procedure
The procedure is as follows:
a) determine the thickness (h) and width (W ) of each prepared specimen;
S
b) initial distance is set to (30 ± 0,05) mm;
c) set the distance of the clamps after compression according to Table 1; the distance between
the clamps after compression is set according to the sample thickness, accurate to
± 0,05 mm, as shown in Table 1;

Dimensions in millimetres
Figure 2 – Schematic of compression jig with test specimen
Table 1 – Settings of distance between the clamps after compression
Specimen thickness, h Clamps distance after compression
h < 0,1 mm (1 ± 0,05) mm
0,1 mm ≤ h < 0,2 mm (2 ± 0,05) mm
0,2 mm ≤ h < 0,3 mm (3 ± 0,05) mm
0,3 mm ≤ h < 0,4 mm (4 ± 0,05) mm
Or user-defined
d) compression rate is set to (50 ± 1) mm/min;
e) pressure holding time after compression is set to (30 ± 0,5) s;
f) clamp the test specimen vertically in the upper and lower compression jigs to ensure that
the marked lines at both end are parallel with the edge of the jigs;
g) test Single-side adhesive specimens in a manner of adhesive-side inward bending, and
double-side asymmetric adhesive specimens in a manner of thicker adhesive-side inward
bending;
h) set the force of test equipment to zero and start the compression process according to the
above settings, and record the test process. The force curve is as shown in Figure 3;

– 10 – IEC 61189-2-501:2022  IEC 2022

Figure 3 – Force curve
i) record the maximum load value L and Load at the end of holding pressure value L of
max end
each specimen.
7 Calculation
a) Calculate the maximum resilience strength per Formula (1):
L
max
F =
max (1)
W
S
where
F is the maximum resilience strength, expressed in millinewtons per millimetres
max
(mN/mm);
L is the maximum load, expressed in millinewtons (mN);
max
W is the measured width of the specimen, expressed in millimetres (mm).
S
b) Calculate the resilience strength at the end of holding pressure as per the Formula (2):
L
end
F = (2)
end
W
S
where
F is the resilience strength at the end of holding pressure, expressed in millinewtons
end
per millimetres (mN/mm);
L is the resilience force at the end of holding pressure, expressed in millinewtons
end
(mN);
W is the measured width of the specimen, expressed in millimetres (mm).
S
c) Calculate the resilience strength retention factor as per the Formula (3):
F
end
K =
Rf (3)
F
max
where
K is the resilience strength retention factor;
Rf
F is the maximum resilience strength;
max
F is the resilience strength at the end of holding pressure
end
8 Report
Report the following:
a) test environment (temp
...