IEC 60068-2-21:2021

Environmental testing - Part 2-21: Tests - Test U: Robustness of terminations and integral mounting devices

IEC 60068-2-21:2021 is applicable to all electrical and electronic components whose terminations or integral mounting devices are liable to be submitted to stresses during normal assembly or handling operations and is also applicable to surface mount devices (SMDs).
This seventh edition cancels and replaces the sixth edition, published in 2006, and IEC 60068‑2‑77:1999. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:  
integration of parts of IEC 60068-2-77 (see Annex X); IEC 60068-2-77 is withdrawn with the publication of this document;
Annex X is added to show the correlation of the clauses and subclauses in this edition of IEC 60068-2-21 with the clauses in IEC 60068-2-21:2006 and IEC 60068-2-77:1999.

Essais d'environnement - Partie 2-21: Essais - Essai U: Robustesse des sorties et des dispositifs de montage incorporés

L’IEC 60068-2-21:2021 s’applique à tous les composants électriques et électroniques dont les sorties ou les dispositifs de montage incorporés sont susceptibles d’être soumis à des contraintes au cours des opérations normales de montage ou de manipulation, et elle s’applique également aux composants pour montage en surface (CMS).
Cette septième édition annule et remplace la sixième édition, parue en 2006, et l’IEC 60068‑2‑77:1999. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:  
intégration des parties de l’IEC 60068-2-77 (voir l’Annexe X). L’IEC 60068-2-77 a été retirée après la publication du présent document;
l’Annexe X a été ajoutée pour montrer la corrélation des articles et des paragraphes de la présente édition de l’IEC 60068-2-21 avec ceux de l’IEC 60068-2-21:2006 et de l’IEC 60068-2-77:1999.

General Information

• Status: Published
• Publication Date: 07-Jul-2021
• ICS: 19.040 - Environmental testing
• ICS: 31.190 - Electronic component assemblies
• Technical Committee: TC 91 - Electronics assembly technology
• Drafting Committee: WG 3 - TC 91/WG 3
• Current Stage: PPUB - Publication issued
• Start Date: 13-Aug-2021
• Completion Date: 08-Jul-2021

Relations

• Replaces: IEC 60068-2-77:1999 - Environmental testing - Part 2-77: Tests - Test 77: Body strength and impact shock
• Effective Date: 05-Sep-2023
• Revises: IEC 60068-2-21:2006 - Environmental testing - Part 2-21: Tests - Test U: Robustness of terminations and integral mounting devices
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60068-2-21
®

Edition 7.0 2021-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE


Environmental testing –
Part 2-21: Tests – Test U: Robustness of terminations and integral mounting
devices

Essais d’environnement –
Partie 2-21: Essais – Essai U: Robustesse des sorties et des dispositifs de
montage incorporés

IEC 60068-2-21:2021-07(en-fr)

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---------------------- Page: 2 ----------------------
IEC 60068-2-21

®


Edition 7.0 2021-07




INTERNATIONAL



STANDARD




NORME


INTERNATIONALE











Environmental testing –

Part 2-21: Tests – Test U: Robustness of terminations and integral mounting

devices



Essais d’environnement –

Partie 2-21: Essais – Essai U: Robustesse des sorties et des dispositifs de


montage incorporés













INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE


INTERNATIONALE




ICS 19.040; 31.190 ISBN 978-2-8322-9999-9




Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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– 2 – IEC 60068-2-21:2021 © IEC 2021
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Tests Ua: Robustness of terminals against axial stresses . 8
4.1 Object . 8
4.2 Application . 8
4.3 General description . 8
4.4 Preconditioning . 8
4.5 Initial measurements . 8
4.6 Test procedures . 9
4.6.1 Test Ua : Tensile . 9
1
4.6.2 Test Ua : Thrust . 10
2
4.7 Final measurements . 11
4.8 Information to be given in the relevant specification . 11
5 Tests Ub: Robustness of terminals against bending stresses . 11
5.1 Object . 11
5.2 Application . 12
5.2.1 General . 12
5.2.2 Pliable terminations . 12
5.2.3 Rigid and all other terminations . 12
5.3 General description . 13
5.4 Preconditioning . 14
5.5 Initial measurements . 14
5.6 Test procedures . 14
5.6.1 Test Ub (for wire and strip terminations). 14
1
5.6.2 Test Ub (for tag terminations) . 16
2
5.6.3 Test Ub Simultaneous bending . 17
3
5.7 Final measurements . 17
5.8 Information to be given in the relevant specification . 17
6 Test Uc: Torsion . 18
6.1 Object . 18
6.2 Application . 18
6.3 General description . 18
6.4 Preparation of the specimen . 18
6.5 Initial measurements . 18
6.6 Test procedure . 19
6.7 Final measurements . 20
6.8 Information to be given in the relevant specification . 20
7 Test Ud: Torque . 20
7.1 Object . 20
7.2 Application . 20
7.3 General description . 21
7.4 Preconditioning . 21
7.5 Initial measurements . 21

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IEC 60068-2-21:2021 © IEC 2021 – 3 –
7.6 Test procedure . 21
7.6.1 Terminations with threaded studs or screws . 21
7.6.2 Other test configurations. 23
7.7 Final measurements . 23
7.8 Information to be given in the relevant specification . 23
8 Test Ue: Robustness of terminations for SMD in the mounted state . 24
8.1 Object . 24
8.2 Application . 24
8.3 Substrate for test method Ue . 24
8.4 Mounting . 26
8.4.1 Dimensions . 26
8.4.2 Possible mounting methods . 26
8.4.3 Mounting method for substrate bending, pull-off, push-off and shear . 26
8.5 Preconditioning . 27
8.6 Initial measurements . 27
8.7 Test methods . 27
8.7.1 Test Ue : Substrate bending test . 27
1
8.7.2 Test Ue : Pull-off and push-off test . 28
2
8.7.3 Test Ue : Shear test . 30
3
8.8 Final measurements . 32
8.8.1 Recovery . 32
8.8.2 Visual examination of terminations . 32
8.8.3 Electrical characteristics . 32
8.8.4 Hidden defect . 32
8.9 Information to be given in the relevant specification . 32
9 Test Uf: Robustness of component body . 34
9.1 Object . 34
9.2 Application . 34
9.3 General description . 34
9.4 Preconditioning . 34
9.5 Initial measurement . 34
9.6 Test procedure . 34
9.6.1 Test Uf : Body strength . 34
1
9.6.2 Test Uf : Impact shock . 36
2
9.7 Final measurements . 38
9.7.1 Recovery . 38
9.7.2 Visual examination . 39
9.7.3 Electrical characteristics . 39
9.7.4 Hidden defect . 39
9.8 Information to be given in the relevant specification . 39
Annex X (informative) Cross-reference for references to the previous editions of this
document . 40
X.1 Cross-reference for references to the previous edition of IEC 60068‑2‑21 . 40
X.2 Cross-reference for references to the last edition of IEC 60068‑2‑77 . 41
Bibliography . 43

Figure 1 – Direction of the applied pull force F in test Ua . 9
p 1

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– 4 – IEC 60068-2-21:2021 © IEC 2021
Figure 2 – Direction of the applied thrust F in test Ua . 10
t 2
Figure 3 – Displacement of pliable lead wires in test Ub . 12
Figure 4 – Bending force applied to a specimen with non-pliable terminations . 13
Figure 5 – Sequential test procedure of test Ub, Method 1 . 15
Figure 6 – Sequential test procedure of test Ub, Methods 2 and 3. 16
Figure 7 – Clamp for the testing of short terminations . 17
Figure 8 – Preparatory bending of a lead wire for test Uc . 18
Figure 9 – Torsion test method 1: Rotation of clamped specimen body . 19
Figure 10 – Torsion test method 2: Rotation of clamped other lead wire. 20
Figure 11 – Assembly for the torque test applied to a threaded stud . 22
Figure 12 – Preparation of a threaded termination for the torque test . 22
Figure 13 – Assembly for the torque test applied to an embedded nut . 23
Figure 14 – Example of substrate for test method Ue . 25
Figure 15 – Substrate bending test . 28
Figure 16 – Test Ue , pull-off test . 29
2
Figure 17 – Test Ue , push-off test . 30
2
Figure 18 – Test Ue , shear test . 31
3
Figure 19 – SMD Body strength test Uf applied to a rectangular specimen . 35
1
Figure 20 – SMD Body strength test Uf applied to a MELF specimen . 36
1
Figure 21 – Example of an apparatus for test Uf . 37
2
Figure 22 – Example of a piston . 37
Figure 23 – Examples of the application of the SMD Body impact shock test Uf . 38
2

Table 1 – Selection of test methods suitable for specific terminations/leads . 7
Table 2 – Value of applied pull force for test Ua . 10
1
Table 3 – Value of applied thrust for test Ua . 11
2
Table 4 – Value of applied force for test Ub . 13
Table 5 – Torque severity . 21
Table X.1 – Cross-reference to clauses . 40
Table X.2 – Cross-reference to figures . 41
Table X.3 – Cross reference to tables . 41
Table X.4 – Cross-reference to clauses . 42
Table X.5 – Cross-reference to figures . 42

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IEC 60068-2-21:2021 © IEC 2021 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

ENVIRONMENTAL TESTING –

Part 2-21: Tests – Test U: Robustness of
terminations and integral mounting devices

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
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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.
International Standard IEC 60068-2-21 has been prepared by IEC technical committee 91:
Electronics assembly technology.
This seventh edition cancels and replaces the sixth edition, published in 2006, and
IEC 60068-2-77:1999. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) integration of parts of IEC 60068-2-77 (see Annex X); IEC 60068-2-77 is withdrawn with the
publication of this document;
b) Annex X is added to show the correlation of the clauses and subclauses in this edition of
IEC 60068-2-21 with the clauses in IEC 60068-2-21:2006 and IEC 60068-2-77:1999.

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– 6 – IEC 60068-2-21:2021 © IEC 2021
The text of this International Standard is based on the following documents:
FDIS Report on voting
91/1732/FDIS 91/1742/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.
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 complete list of all parts comprising the IEC 60068 series, under the general title
Environmental testing, 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.

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IEC 60068-2-21:2021 © IEC 2021 – 7 –
ENVIRONMENTAL TESTING –

Part 2-21: Tests – Test U: Robustness of
terminations and integral mounting devices



1 Scope
This part of IEC 60068 is applicable to all electrical and electronic components whose
terminations or integral mounting devices are liable to be submitted to stresses during normal
assembly or handling operations and is also applicable to surface mount devices (SMDs).
The recommended test methods suitable for specific terminations/lead of devices are shown in
Table 1.
Table 1 – Selection of test methods suitable for specific terminations/leads
Test method Component Mounted/not See Clause
mounted
Test Type
Ua Tensile Leaded devices Not mounted Clause 4
1
Ua Thrust Leaded devices Not mounted Clause 4
2
Ub Bending Leaded devices Not mounted Clause 5
Uc Torsion Leaded devices Not mounted Clause 6
Ud Torque Threaded stud, screw or Not mounted Clause 7
other terminations
Ue Substrate Surface mount devices Mounted Clause 8
1
bending
Ue Pull/push Surface mount devices Mounted Clause 8
2
Ue Shear Surface mount devices Mounted Clause 8
3
Uf Body Surface mount devices Not mounted Clause 9
1
strength
Impact
Uf Surface mount devices Not mounted Clause 9
2
shock

2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
IEC 60068-1:2013, Environmental testing – Part 1: General and guidance
IEC 60068-2-58:2015, Environmental testing – Part 2-58: Tests – Test Td – Test methods for
solderability, resistance to dissolution of metallization and to soldering heat of surface mounting
devices (SMD)
IEC 60194-2, Printed board design, manufacture and assembly – Vocabulary – Part 2: Common
usage in electronic technologies as well as printed board and electronic assembly technologies

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– 8 – IEC 60068-2-21:2021 © IEC 2021
IEC 61191-2, Printed board assemblies – Part 2: Sectional specification – Requirements for
surface mount soldered assemblies
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60194-2 and the
following 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
integral mounting device
auxiliary means to make a mechanical connection of a terminal or other mounting element to
the inside of the component and its case
Note 1 to entry: Such means can be a stud, a nut, a bolt, or similar mechanical parts for fixing.
4 Tests Ua: Robustness of terminals against axial stresses
4.1 Object
The purpose of these tests is to verify that the terminations and their attachments to the body
of the component will withstand such axial stresses as are likely to be applied during normal
assembly or handling operations.
4.2 Application
The relevant specification shall state whether this test is applicable. It shall be carried out on
all the terminations, except where a component has more than three
...