IEC 60068-2-77:1999 pdf download.Environmental testing – Part 2-77: Tests – Test 77: Body strength and impact shock
1 Scope and object
This part of IEC 60068 provides test methods applicable to surface mounting devices (SMDs)
made of glass or sintered materials such as capacitors, resistors and inductors incorporating
ferrites. Two test methods exist: body strength and impact shock.
The object of both tests is to evaluate the mechanical stresses applied to SMDs during and
after mounting; these tests look at different mechanical stresses. The relevant component
specification shall specify which test method or methods are applicable.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 60068. For dated references, subsequent amendments
to, or revisions of, any of these publications do not apply. However, parties to agreements
based on this part of IEC 60068 are encouraged to investigate the possibility of applying the
most recent editions of the normative documents indicated below. For undated references, the
latest edition of the normative document referred to applies. Members of IEC and ISO maintain
registers of currently valid International Standards.
IEC 601 94:—, Terms and definitions for printed circuits
3 Terms and definitions
For the purpose of this part of IEC 60068, the terms and definitions given in IEC 601 94 apply.
4 Test methods Body strength
This test evaluates the strength of the body of the SMD against external static forces which are applied to them during mounting, in the direction perpendicular to the printed board on which the SMDs are mounted. NOTE The test evaluates the sturdiness of the body of the SMDs and not the adhesive strength at the interface between the termination and solder of the body. These latter tests are described in IEC 60068-2-21 . This test simulates the static force applied to SMDs during picking up and centering in a placement process with a rather slow speed mounting machine in which the forces are mainly of a static nature. A static force can have a different influence on a device from that of a dynamic force, whose effects can be evaluated by a test separately described as an impact shock test. This simulates the mechanical stress applied to the SMDs, during and after mounting the SMDs on a printed board. This test shall be referred to in the relevant detail specification.
4.2 Impact shock
This test evaluates the physical resistance of SMDs against impact shock. This test simulates the dynamic forces applied by picking and placing tools on a high speed mounting machine. The influence of a dynamic force on a device can differ from the influence of a static force. This test shall be referred to in the relevant detail specification.
5 Equipment
a) Body strength equipment
The equipment shall be able to apply the specified force to the specimen and maintain the
test load for the specified duration. The length ( L ) of the tip of the pushing tool shall be
wider than the width ( W ) of the specimen under test. Unless otherwise specified in the
relevant specification, the shape of the tip of the pushing tool shall be chamfered with a
radius of 0,5 mm. The thickness of the pushing tool is not specified (see figure 1 ). If this
specification cannot be applied due to the shape or construction of the specimen under test
or for any other reason, the shape of the pushing tool shall be specified in the relevant
specification.
b) Impact shock equipment
The equipment shall be able to apply the specified potential energy to the specimen. The
principle of the equipment is given in figure 4. The potential energy is given by the following
formula:
IEC 60068-2-77:1999 pdf download
