ASTM F1896-10
(Test Method)Test Method for Determining the Electrical Resistivity of a Printed Conductive Material
Test Method for Determining the Electrical Resistivity of a Printed Conductive Material
SIGNIFICANCE AND USE
Resistivity is useful to suppliers and manufacturers as follows:
when designing membrane switch interface circuitry,
when selecting the appropriate conductive material,
for conductive material quality verification, and
for conductive material cure optimization and quality control.
SCOPE
1.1 This test method covers the determination of the electrical resistivity of a conductive material as used in the manufacture of a membrane switch.
1.2 This test method is not suitable for measuring force sensitive conductive materials.
1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.4 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: F1896 − 10
TestMethod for
Determining the Electrical Resistivity of a Printed
1
Conductive Material
This standard is issued under the fixed designation F1896; 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 3.1.4 for conductive material cure optimization and quality
control.
1.1 This test method covers the determination of the elec-
trical resistivity of a conductive material as used in the
4. Interferences
manufacture of a membrane switch.
4.1 The precision and bias of this test method are under
1.2 This test method is not suitable for measuring force
investigation.Theaccuracyoftheresistivitydeterminationwill
sensitive conductive materials.
be improved as the number of squares of the resistance test
1.3 The values stated in inch-pound units are to be regarded
strip is increased. The accuracy of the resistivity determination
as standard. The values given in parentheses are mathematical
will be improved as the width (W) of the circuitry test pattern
conversions to SI units that are provided for information only
is increased. Some conductive materials’ resistivity are sensi-
and are not considered standard.
tive to temperature and the temperature of the test specimen
should be noted and recorded.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
5. Apparatus
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
5.1 Resistance Measuring Device, (that is, ohm meter)
bility of regulatory limitations prior to use.
equipped with test leads and probes. The device should be
capable of measuring resistances up to 100 MΩ with an
2. Terminology
accuracyofgreaterthan1.5 %offullscalereading.Testprobes
2.1 Definitions:
should have tips that are 25 to 250 % of the width (W)ofthe
2.1.1 membrane switch—a momentary switching device in printed conductor test pattern.
which at least one contact is on, or made of, a flexible
5.2 Test Surface, to be flat, smooth, unyielding and larger
substrate.
than switch under test.
2.1.2 circuit/test pattern resistance—electrical resistance as
5.3 Thickness Measuring Device, capable of measuring to
measured between two terminations of a circuit trace.
the nearest 0.00005 in. (1.25 µm).
2.1.3 square—A geometric unit of a printed conductive
5.4 Dimensional Measuring Device, capable of measuring
circuit trace/pattern obtained by dividing the length (L)ofthe
to the nearest 0.001 in. (25 µm).
printed conductive circuit trace/pattern by its width (W).
2.1.4 resistivity—ohms per square per mil of a conductive
6. Test Specimen
material.
6.1 A resistance test strip of printed and cured conductive
material with a minimum length (L) to width (W) ratio of 50:1
3. Significance and Use
(equal to or greater than 50 squares). A pattern of membrane
3.1 Resistivity is useful to suppliers and manufacturers as
switch circuitry is sufficient if a straight measurable strip, with
follows:
a minimum length (L) to width (W) ratio of 50:1 (equal to or
3.1.1 when designing membrane switch interface circuitry,
greater than 50 squares), is available. The accuracy of the
3.1.2 when selecting the appropriate conductive material,
resistivity determination will be improved as the number of
3.1.3 for conductive material quality verification, and
squares of the resistance test strip is increased.
1 7. Procedure
This test method is under the jurisdiction of Committee F01 on Electronics, and
is the direct responsibility of Subcommittee F01.18 on Membrane Switches.
7.1 Pre-Test Setup:
Current edition approved May 1, 2010. Published June 2010. Originally
7.1.1 Secure switch/test pattern (that is, printed and cured
approved in 1998. Last previous edition approved in 2004 as F1896 - 98 (2004).
DOI: 10.1520/F1896-10. conductive material) on the test surface.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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F1896 − 10
7.1.2 Measure the geometry of the test pattern as follows: the measured thickness (t) in mils. Record the resistivity of the
7.1.2.1 Measure the length (L) of the printed test pattern. conductive material (ohms per square per mil).
7.1.2.2 Measure the width (W) of the printed test pattern. 7.3.4 Examples:
7.1.2.3 Divide the length (L) by the width (W) to calculate 7.3.4.1 Example No. 1 is as follows:
thenumberofsquaresoftheprintedtestpattern.Shouldbe≥50
Resistance Measurement: 3.0 Ω
Thickness (t) Measurement: 0.50 mils (12.5 µm)
squar
...
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:F1896–98(Reapproved2004) Designation: F1896 – 10
Test Method for
Determining the Electrical Resistivity of a Printed
1
Conductive Material
This standard is issued under the fixed designation F1896; 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 covers the determination of the electrical resistivity of a conductive material as used in the manufacture
of a membrane switch.
1.2 This test method is not suitable for measuring force sensitive conductive materials.
1.3The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information
only.
1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.4 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 membrane switch—a momentary switching device in which at least one contact is on, or made of, a flexible substrate.
2.1.2 circuit/test pattern resistance—electrical resistance as measured between two terminations of a circuit trace.
2.1.3 square—A geometric unit of a printed conductive circuit trace/pattern obtained by dividing the length (L) of the printed
conductive circuit trace/pattern by its width (W).
2.1.4 resistivity—ohms per square per mil of a conductive material.
3. Significance and Use
3.1 Resistivity is useful to suppliers and manufacturers as follows:
3.1.1 when designing membrane switch interface circuitry,
3.1.2 when selecting the appropriate conductive material,
3.1.3 for conductive material quality verification, and
3.1.4 for conductive material cure optimization and quality control.
4. Interferences
4.1 The precision and bias of this test method are under investigation. The accuracy of the resistivity determination will be
improved as the number of squares of the resistance test strip is increased. The accuracy of the resistivity determination will be
improved as the width (W) of the circuitry test pattern is increased. Some conductive materials’ resistivity are sensitive to
temperature and the temperature of the test specimen should be noted and recorded.
5. Apparatus
4.1
5.1 Resistance Measuring Device, (that is, ohm meter) equipped with test leads and probes. The device should be capable of
measuring resistances up to 100 MV with an accuracy of greater than 1.5 % of full scale reading. Test probes should have tips that
are 25 to 250 % of the width (W) of the printed conductor test pattern.
4.2
5.2 Test Surface, to be flat, smooth, unyielding and larger than switch under test.
4.3
1
This test method is under the jurisdiction of Committee F01 on Electronics , and is the direct responsibility of Subcommittee F01.18 on Membrane Switches.
Current edition approved May 1, 2004.2010. Published June 2004.2010. Originally approved in 1998. Last previous edition approved in 19982004 as F1896 - 98 (2004).
DOI: 10.1520/F1896-98R04.10.1520/F1896-10.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
F1896 – 10
5.3 Thickness Measuring Device, capable of measuring to the nearest 0.00005 in. (1.25 µm).
4.4
5.4 Dimensional Measuring Device, capable of measuring to the nearest 0.001 in. (25 µm).
5.
6. Test Specimen
5.1A6.1 A resistance test strip of printed and cured conductive material with a minimum length (L) to width (W) ratio of 50:1
(equal to or greater than 50 squares). A pattern of membrane switch circuitry is sufficient if a straight measurable strip, with a
minimum length ( L) to width (W) ratio of 50:1 (equal to or greater than 50 squares), is available. The accuracy of the resistivity
determination will be improved as the number of squares of the resistance test strip is increased.
6.
7. Procedure
6.1
7.1 Pre-Test Setup:
67.1.1 Secure switch/test pattern (that is, printed and cured conductive material) on the test surface.
67.1.2
...
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