ASTM F2750-09
(Test Method)Standard Test Method for Determining the Effects of Bending a Membrane Switch or Assembly
Standard Test Method for Determining the Effects of Bending a Membrane Switch or Assembly
SIGNIFICANCE AND USE
Bending of membrane switches or their components can affect their visual appearance, mechanical integrity or electrical functionality. This test method simulates conditions that may be seen during manufacture, installation or use.
Bend testing may be destructive, therefore any samples tested should be considered unfit for future use.
Specific areas of testing include, but are not limited to:
Membrane switch flex tails, and
Any component of a membrane switch that may be subjected to bending.
SCOPE
1.1 This test method establishes a method for the bending of any part of a membrane switch with conductive circuits.
1.1.1 The values given in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: F2750 − 09
StandardTest Method for
Determining the Effects of Bending a Membrane Switch or
1
Assembly
This standard is issued under the fixed designation F2750; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope functionality. This test method simulates conditions that may
be seen during manufacture, installation or use.
1.1 This test method establishes a method for the bending of
any part of a membrane switch with conductive circuits. 3.2 Bend testing may be destructive, therefore any samples
1.1.1 The values given in SI units are to be regarded as the tested should be considered unfit for future use.
standard. The values given in parentheses are for information
3.3 Specific areas of testing include, but are not limited to:
only.
3.3.1 Membrane switch flex tails, and
1.2 This standard does not purport to address all of the
3.3.2 Any component of a membrane switch that may be
safety concerns, if any, associated with its use. It is the
subjected to bending.
responsibility of the user of this standard to establish appro-
4. Interferences
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. 4.1 The following parameters may affect the results of this
test:
2. Terminology
4.1.1 temperature,
4.1.2 humidity, and
2.1 Definitions:
4.1.3 orientation of the conductor (either extension or com-
2.1.1 bend—to force from a straight form into a different
pression) could have significant impact on the results.
and especially a curved one.
NOTE 1—Experience has shown that some conductors recover their
2.1.1.1 Discussion—In this case, no “hard” or angled crease
conductive properties if allowed to stabilize after the dynamic portion of
or fold is to occur. The substrate will only be formed into a
the test. Therefore, continuous monitoring is recommended.
radius.
5. Apparatus
2.1.2 bend cycle—a bend of a sample around a specified
mandrel which is “rolled” in one direction, followed by rolling 5.1 Mandrel, allowed to rotate smoothly around its longitu-
in the opposite direction, returning the sample to its original dinal axis, rigid, low friction smooth surface. Diameter to be
position (see Fig. 1). specified.
2.1.3 mandrel—a cylindrically shaped metal rod, such as a
5.2 Fixture to hold test sample securely in place in a vertical
brazing or drill rod.
manner (refer to Fig. 1).
2.1.4 membrane switch—a momentary switching device in
5.3 Mechanism capable of providing a consistent force and
which at least one contact is on, or made of, a flexible
rate of pull to the sample.
substrate.
5.4 Equipment for the monitoring and recording of resis-
2.1.5 membrane switch tail—a flexible portion of a mem-
tance.
brane switch used for input/output connection.
NOTE 2—Experience has shown that some conductors recover their
conductive properties if allowed to stabilize after the dynamic portion of
the test. Therefore, continuous monitoring is recommended.
3. Significance and Use
3.1 Bending of membrane switches or their components can
6. Test Samples
affecttheirvisualappearance,mechanicalintegrityorelectrical
6.1 The test samples may be components, tail assembles or
finished switches. If the sample length is too short for the test
fixture, a sample coupon of the same construction (layer to
1
This test method is under the jurisdiction of ASTM Committee F01 on
layer) must be provided (minimum; 250 mm length by 25 mm
Electronics and is the direct responsibility of Subcommittee F01.18 on Membrane
Switches. width).
Current edition approved June 15, 2009. Published July 2009. Originally
6.2 The width of the test sample must not exceed the length
approved in 2008. Last previous edition approved in 2008 as F2750-08. DOI:
10.1520/F2750-09. of the mandrel.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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F2750 − 09
FIG. 1 Test Fixture Setup
7. Procedure 7.7 Start test.
7.7.1 Record the closed loop resistance (Ri) - measurement
7.1 Clamponeendofthetestsampletothetestfixture–this
made on the first test cycle. At the end of the test, the “R
is the static end of the test sample.
maximum” value, which is the largest value using a time
7.1.1 Compression Conductor Testing —conductor side of
constant chosen appropriately for the measurement, is re-
the test sample faces the mandrel.
corded.
7.1.2 Extension Conductor Testing —conductor side of the
7.7.2 A cycle is defined as travel from maximum extension
test sample faces away from the mandrel.
to minimum extension and bac
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:F2750–08 Designation:F2750–09
Standard Test Method for
Determining the Effects of Bending a Membrane Switch or
1
Assembly
This standard is issued under the fixed designation F 2750; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method establishes a method for the bending of any part of a membrane switch with conductive circuits.
1.1.1 The values given in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Terminology
2.1 Definitions:
2.1.1 bend—to force from a straight form into a different and especially a curved one.
2.1.1.1 Discussion—In this case, no “hard” or angled crease or fold is to occur. The substrate will only be formed into a radius.
2.1.2 bend cycle—a bend of a sample around a specified mandrel which is “rolled” in one direction, followed by rolling in the
opposite direction, returning the sample to its original position (see Fig. 1).
2.1.3 mandrel—a cylindrically shaped metal rod, such as a brazing or drill rod.
2.1.4 membrane switch—a momentary switching device in which at least one contact is on, or made of, a flexible substrate.
2.1.5 membrane switch tail—a flexible portion of a membrane switch used for input/output connection.
3. Significance and Use
3.1 Bending of membrane switches or their components can affect their visual appearance, mechanical integrity or electrical
functionality. This test method simulates conditions that may be seen during manufacture, installation or use.
3.2 Bend testing may be destructive, therefore any samples tested should be considered unfit for future use.
3.3 Specific areas of testing include, but are not limited to:
3.3.1 Membrane switch flex tails, and
3.3.2 Any component of a membrane switch that may be subjected to bending.
4. Interferences
4.1 The following parameters may affect the results of this test:
4.1.1 temperature,
4.1.2 humidity, and
4.1.3 orientation of the conductor (either extension or compression) could have significant impact on the results.
NOTE 1—Experience has shown that some conductors recover their conductive properties if allowed to stabilize after the dynamic portion of the test.
Therefore, continuous monitoring is recommended.
5. Apparatus
5.1 Mandrel, allowed to rotate smoothly around its longitudinal axis, rigid, low friction smooth surface. Diameter to be
specified.
5.2 Fixture to hold test sample securely in place in a vertical manner (refer to Fig. 1).
5.3 Mechanism capable of providing a consistent force and rate of pull to the sample.
5.4 Equipment for the monitoring and recording of resistance.
1
This test method is under the jurisdiction of ASTM Committee F01 on Electronics and is the direct responsibility of Subcommittee F01.18 on Membrane Switches.
Current edition approved Nov. 1, 2008. Published December 2008.
Current edition approved June 15, 2009. Published July 2009. Originally approved in 2008. Last previous edition approved in 2008 as F 2750-08.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
F2750–09
FIG. 1 Test Fixture Setup
NOTE 2—Experience has shown that some conductors recover their conductive properties if allowed to stabilize after the dynamic portion of the test.
Therefore, continuous monitoring is recommended.
6. Test Samples
6.1 Thetestsamplesmaybecomponents,tailassemblesorfinishedswitches.Ifthesamplelengthistooshortforthetestfixture,
a sample coupon of the same construction (layer to layer) must be provided (minimum; 250 mm length by 25 mm width).
6.2 The width of the test sample must not exceed the length of the mandrel.
7. Procedure
7.1 Clamp one end of the test sample to the test fixture – this is the static end of the test sample.
7.1.1 Compression Conductor Testing —conductor side of the test sample faces the mandrel.
7.1.2 Extension Conductor Testing —conductor side of the test sample faces away from the mandrel.
7.2 Loop the uns
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