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

IEC 60068-2-21:2006 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. This edition includes the following significant technical changes with respect to the previous edition:
- Addition of torque severity for nominal thread diameter of 8 mm in Test Ud: torque in accordance with IEC 60252-2 (see table 5);
- Modification of substrate specification and mounting method describing lead-free solder in Test Ue (see Figure 5 and 8.3.3 et al.);
- Modification of test jig and test condition in Test Ue1: substrate bending test (see Figure 7 et al.);
- Change of pushing force from 10 N to 5 N in Test Ue3: shear test (see 8.5.3.2). The contents of the corrigendum of January 2012 have been included in this copy.

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

La CEI 60068-2-21:2006 est applicable 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. La présente édition inclut les modifications techniques significatives suivantes par rapport à l'édition antérieure:
- Ajout de la sévérité du couple pour le diamètre nominal du filetage de 8 mm à l'Essai Ud: essai de couple, conformément à la CEI 60252-2 (voir le tableau 5);
- Modification de la spécification du substrat et de la méthode de montage décrivant l'alliage à braser sans plomb, à l'Essai Ue (voir la Figure 5 et le 8.3.3 et al.);
- Modification du gabarit d'essai et des conditions d'essai concernant l'Essai Ue1: essai de pliage du substrat (voir la Figure 7 et al.);
- Modification de la force de poussée passant de 10 N à 5 N dans l'Essai Ue3: essai de cisaillement (voir le 8.5.3.2). Le contenu du corrigendum de janvier 2012 a été pris en considération dans cet exemplaire.

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Status
Published
Publication Date
21-Jun-2006
Drafting Committee
Current Stage
DELPUB - Deleted Publication
Start Date
31-Jul-2017
Completion Date
08-Jul-2021
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IEC 60068-2-21
®

Edition 6.0 2006-06
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 60068-2-21:2006

---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 60068-2-21
®

Edition 6.0 2006-06
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
PRICE CODE
INTERNATIONALE
CODE PRIX U
ICS 19.040; 31.190 ISBN 978-2-88912-734-4

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

---------------------- Page: 3 ----------------------
– 2 – 60068-2-21  IEC:2006
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Test Ua : tensile . 7
1
3.1 Object . 7
3.2 General description . 7
3.3 Preconditioning . 7
3.4 Initial measurements . 7
3.5 Test method . 7
3.6 Final measurements . 8
3.7 Information to be given in the relevant specification . 8
4 Test Ua : thrust . 9
2
4.1 Object . 9
4.2 General description . 9
4.3 Preconditioning . 9
4.4 Initial measurements . 9
4.5 Test method . 9
4.6 Final measurements . 10
4.7 Information to be given in the relevant specification . 10
5 Test Ub: bending . 10
5.1 Object . 10
5.2 General description . 11
5.3 Preconditioning . 11
5.4 Initial measurements . 11
5.5 Test method . 11
5.6 Final measurements . 13
5.7 Information to be given in the relevant specification . 14
6 Test Uc: torsion . 14
6.1 Object . 14
6.2 Preconditioning . 14
6.3 Initial measurements . 14
6.4 Test method . 14
6.5 Final measurements . 15
6.6 Information to be given in the relevant specification . 15
7 Test Ud: torque . 15
7.1 Object . 15
7.2 General description . 15
7.3 Preconditioning . 15
7.4 Initial measurements . 15
7.5 Test method . 16
7.6 Final measurements . 16
7.7 Information to be given in the relevant specification . 16

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60068-2-21  IEC:2006 – 3 –
8 Test Ue: robustness of terminations for SMD in the mounted state . 17
8.1 Object . 17
8.2 General description . 17
8.3 Mounting . 18
8.4 Initial measurements . 19
8.5 Test methods . 19
8.6 Final measurements . 21
8.7 Information to be given in the relevant specification . 22

Figure 1 – Clamp for the testing of short terminations . 13
Figure 2 – Sketches showing direction by arrow heads of application of forces
Test Ua : tensile and test Ua : thrust . 23
1 2
Figure 3 – Sketches showing test procedure for test Ub: bending (see 5.5.2.1 and 5.5.2.3) . 24
Figure 4 – Diagrams showing test procedure for test Uc: torsion test for wire terminations. 25
Figure 5 – Example of substrate for test method Ue (also suitable for electrical test) . 26
1
Figure 6 – Example of substrate for test methods Ue and Ue
2 3
(also suitable for electrical test) . 26
Figure 7 – Bending jig for test Ue . 27
1
Figure 8 – Example of a push-off test substrate . 27
Figure 9 – Force test Ue – pull-off . 28
2
Figure 10 – Example of a force application pushing tool for test Ue – push-off . 28
2
Figure 11 – Example of the shear (adhesion) test – Ue . 28
3

Table 1 – Application . 6
Table 2 – Value of applied force for test Ua . 8
1
Table 3 – Value of applied force for test Ua . 10
2
Table 4 – Value of applied force for test Ub . 12
Table 5 – Torque severity . 16

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– 4 – 60068-2-21  IEC:2006
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 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 may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for 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
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
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 sixth edition cancels and replaces the fifth edition, published in 1999, and constitutes a
technical revision.
This edition includes the following significant technical changes with respect to the previous
edition
– Addition of torque severity for nominal thread diameter of 8 mm in Test Ud: torque in
accordance with IEC 60252-2 (see table 5)
– Modification of substrate specification and mounting method describing lead-free solder in
Test Ue (see Figure 5 and 8.3.3 et al.)

---------------------- Page: 6 ----------------------
60068-2-21  IEC:2006 – 5 –
– Modification of test jig and test condition in Test Ue : substrate bending test (see Figure 7
1
et al.)
– Change of pushing force from 10 N to 5 N in Test Ue : shear test (see 8.5.3.2)
3
This bilingual version corresponds to the monolingual English version, published in 2006-06.
The text of this standard is based on the following documents:
FDIS Report on voting
91/582/FDIS 91/607/RVD

Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
The French version of this standard has not been voted upon.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
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 publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.

The contents of the corrigendum of January 2012 have been included in this copy.

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– 6 – 60068-2-21  IEC:2006
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.
Table 1 provides details of the applicable tests.
Table 1 – Application
Test Type Component Mounted/not mounted
Ua Tensile Leaded devices Not mounted
1
Ua Thrust Leaded devices Not mounted
2
Ub Bending Leaded devices Not mounted
Uc Torsion Leaded devices Not mounted
Ud Torque Threaded stud or screw termination Not mounted
Ue Bending Surface mounted devices Mounted
1
Ue Pull/push Surface mounted devices Mounted
2
Ue Shear Surface mounted devices Mounted
3
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.
IEC 60068-1:1988, Environmental testing – Part 1: General and guidance
Amendment 1 (1992)
IEC 60068-2-20:1979, Environmental testing – Part 2: Tests – Test T: Soldering
Amendment 2 (1987)
IEC 60068-2-58:2004, 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 60068-2-61:1991, Environmental testing – Part 2: Tests – Test Z/ABDM: Climatic
sequence
IEC 61249-2-7:2002, Materials for printed boards and other interconnecting structures –
Part 2-7: Reinforced base materials clad and unclad – Epoxide woven E-glass laminated
sheet of defined flammability (vertical burning test), copper-clad
IEC 61188-5 (all parts), Printed boards and printed board assemblies – Design and use
IEC 61190-1-2:2002, Attachment materials for electronic assembly – Part 1-2: Requirements
for soldering pastes for high quality interconnections in electronics assembly

---------------------- Page: 8 ----------------------
60068-2-21  IEC:2006 – 7 –
IEC 61191-2:1998, Printed board assemblies – Part 2: Sectional specification – Requirements
for surface mount soldered assemblies
ISO 272:1982, Fasteners – Hexagon products – Widths across flats
ISO 9453:1990, Soft solder alloys – Chemical compositions and forms
3 Test Ua : tensile
1
This test is applicable to all types of terminations.
3.1 Object
The purpose of this test is to verify that the terminations and attachment of the terminations to
the body of the component will withstand such axial stresses as are likely to be applied during
normal assembly or handling operations.
3.2 General description
With the termination in its normal position and the component held by its body, a force is
applied to the termination in the direction of its axis and acting in a direction away from the
body of the component. The force shall be applied progressively (without any shock) and then
maintained for a period of 10 s ± 1 s.
3.3 Preconditioning
The method of preconditioning shall be as prescribed in the relevant specification.
3.4 Initial measurements
The specimen shall be visually inspected and electrically and mechanically checked, as
required by the relevant specification.
3.5 Test method
Unless otherwise specified in the relevant specification, the test method shall be as follows:
Refer to Figure 2a.
3.5.1 Application
This test applies to all types of terminations. It shall be carried out on all the terminations,
except where a component has more than three terminations, in which case the specification
shall state the number of terminations per component to be tested. The test shall be carried
out in such a manner that all the terminations of the component have an equal probability of
being subjected to test.
3.5.2 Procedure
With the termination in its normal position and the component held by its body, a force with a
value as stated in Table 2 shall be applied to the termination in the direction of its axis and
acting in a direction away from the body of the component. The force shall be applied
progressively (without any shock) and then maintained for a period of 10 s ± 1 s.

---------------------- Page: 9 ----------------------
– 8 – 60068-2-21  IEC:2006
The value of the applied force is as follows:
a) Wire terminations (circular section or strip) or pins
The value of the force applied shall be that indicated in Table 2.
Insulated wires shall be stripped of the insulation at the point at which the load is applied.
Stranded wires shall be united mechanically at the point of application of the load (such as
by soldering or knotting), prior to the application of the load. Where the technical features
of insulated or stranded wires may give rise to difficulties during the stripping, joining or
knotting operations and be liable to cause dispute for the test results, such operations
shall be in accordance with the relevant specification or, where necessary, with the
instructions of the component manufacturer.
Table 2 – Value of applied force for test Ua
1
a
Nominal cross-sectional area (S) Corresponding diameter (d) for Force with tolerance of ±10 %
circular-section wires
2
mm mm N
     s ≤ 0,05      d ≤ 0,25 1
0,05 < s ≤ 0,10 0,25 < d ≤ 0,35 2,5
0,10 < s ≤ 0,20 0,35 < d ≤ 0,50 5
0,20 < s ≤ 0,50 0,50 < d ≤ 0,80 10
0,50 < s ≤ 1,20 0,80 < d ≤ 1,25 20
     s > 1,20      d > 1,25 40
a
For circular-section wires, strips or pins, the nominal cross-sectional area is equal to the value calculated
from the nominal dimension(s) given in the relevant specification. For stranded wires, the nominal cross-
sectional area is obtained by taking the sum of the cross-sectional areas of the individual strands of the
conductor specified in the relevant specification.

b) Other terminations (tag terminations, threaded studs, screws, terminals, etc.)
The value of the force to be applied shall be given in the relevant specification.
3.6 Final measurements
The specimen shall be visually inspected and electrically and mechanically checked, as
required by the relevant specification.
3.7 Information to be given in the relevant specification
 Subclause
a) Method of preconditioning 3.3
b) Initial measurements 3.4
c) Number of terminations to be tested, if more than three 3.5.1
d) Force (for oversized and other terminations) 3.5.2
e) Details of stripping, joining or knotting operations, if necessary 3.5.2
f) Final measurements 3.6

---------------------- Page: 10 ----------------------
60068-2-21  IEC:2006 – 9 –
4 Test Ua : thrust
2
4.1 Object
The purpose of this test is to verify that the terminations and attachment of the terminations to
the body of the component will withstand such thrusts as are likely to be applied during
normal assembly or handling operations. This test applies only to specimens of small
dimensions and of low mass, to the exclusion of equipment and assemblies.
NOTE This test does not apply to flexible terminations. The tests for flexible terminations are given in a) and b)
of 5.1.
4.2 General description
With the termination in its normal position and the component held by its body, thrust is
applied to the termination as close as possible to the body of the component, but leaving a
clear 2 mm of wire between the body of the component and the nearest point of the device
applying the force. The force shall be applied progressively (without any shock) and then
maintained for a period of 10 s ± 1 s.
4.3 Preconditioning
The method of preconditioning shall be as prescribed in the relevant specification.
4.4 Initial measurements
The specimen shall be visually inspected and electrically and mechanically checked, as
required by the relevant specification.
4.5 Test method
Refer to Figure 2b.
4.5.1 Application
The relevant specification shall state whether this test is applicable. When applicable, it shall
be carried out on all the terminations, except where a component has more than three
terminations, in which case the specification shall state the number of terminations per
component to be tested. The test shall be carried out in such a manner that all the
terminations of the component have an equal probability of being subjected to test. The
relevant specification shall define the direction of applied force.
4.5.2 Procedure
With the termination in its normal position and the component held by its body, thrust shall be
applied to the termination as close as possible to the body of the component, but leaving a
clear 2 mm of wire between the body of the component and the nearest point of the device
applying the force. The force shall be applied progressively (without any shock) and then
maintained for a period of 10 s ± 1 s.
The value of the applied force is as follows:
a) Wire terminations (circular-section or strip) or pins
The value of the force applied shall be as given in Table 3.

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– 10 – 60068-2-21  IEC:2006
Table 3 – Value of applied force for test Ua
2
a
Nominal cross-sectional area (S) Corresponding diameter (d) for
Force with tolerance of ±10 %
circular-section wire

2
mm mm N
     s ≤ 0,05      d ≤ 0,25 0,25
0,05 < s ≤ 0,10 0,25 < d ≤ 0,35 0,5
0,10 < s ≤ 0,20 0,35 < d ≤ 0,50 1
0,20 < s ≤ 0,50 0,50 < d ≤ 0,80 2
0,50 < s ≤ 1,20 0,80 < d ≤ 1,25 4
     s > 1,20      d > 1,25 8
a
For circular-section wires, strips or pins, the nominal cross-sectional area is equal to the value calculated from
the nominal dimension(s) given in the relevant specification.

Insulated wires shall be stripped of the insulation at the point at which the load is applied.
Where the technical features of insulated wires may give rise to difficulties during the
stripping, and be liable to cause dispute for the test results, such operations shall be in
accordance with the relevant specification or, where necessary, with the instructions of the
component manufacturer.
b) Other terminations (tag terminations, threaded studs, screws, terminals, etc.)
The value of the force to be applied shall be given in the relevant specification.
4.6 Final measurements
The specimen shall be visually inspected and electrically and mechanically checked, as
required by the relevant spe
...

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