ASTM F1896-98(2004)

Test Method for Determining the Electrical Resistivity of a Printed Conductive Material

SIGNIFICANCE AND USE
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.
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 the standard. The values given in parentheses are for information only.
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.

General Information

• Status: Historical
• Publication Date: 30-Apr-2004
• ICS: 31.180 - Printed circuits and boards
• Technical Committee: F01 - Electronics
• Drafting Committee: F01.18 - Printed Electronics

Relations

• Replaces: ASTM F1896-98 - Test Method for Determining the Electrical Resistivity of a Printed Conductive Material
• Effective Date: 01-May-2004
• Replaced By: ASTM F1896-10 - Test Method for Determining the Electrical Resistivity of a Printed Conductive Material
• Effective Date: 01-May-2010

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information.
Designation:F1896–98(Reapproved2004)
Test Method for
Determining the Electrical Resistivity of a Printed
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. Apparatus
manufacture of a membrane switch.
4.1 Resistance Measuring Device, (that is, ohm meter)
1.2 This test method is not suitable for measuring force
equipped with test leads and probes. The device should be
sensitive conductive materials.
capable of measuring resistances up to 100 MV with an
1.3 The values stated in inch-pound units are to be regarded
accuracyofgreaterthan1.5 %offullscalereading.Testprobes
as the standard. The values given in parentheses are for
should have tips that are 25 to 250 % of the width (W)ofthe
information only.
printed conductor test pattern.
1.4 This standard does not purport to address all of the
4.2 Test Surface, to be flat, smooth, unyielding and larger
safety concerns, if any, associated with its use. It is the
than switch under test.
responsibility of the user of this standard to establish appro-
4.3 Thickness Measuring Device, capable of measuring to
priate safety and health practices and determine the applica-
the nearest 0.00005 in. (1.25 µm).
bility of regulatory limitations prior to use.
4.4 Dimensional Measuring Device, capable of measuring
2. Terminology to the nearest 0.001 in. (25 µm).
2.1 Definitions:
5. Test Specimen
2.1.1 membrane switch—a momentary switching device in
5.1 A resistance test strip of printed and cured conductive
which at least one contact is on, or made of, a flexible
material with a minimum length (L) to width (W) ratio of 50:1
substrate.
(equal to or greater than 50 squares). A pattern of membrane
2.1.2 circuit/test pattern resistance—electrical resistance as
switch circuitry is sufficient if a straight measurable strip, with
measured between two terminations of a circuit trace.
a minimum length (L) to width (W) ratio of 50:1 (equal to or
2.1.3 square—A geometric unit of a printed conductive
greater than 50 squares), is available. The accuracy of the
circuit trace/pattern obtained by dividing the length (L)ofthe
resistivity determination will be improved as the number of
printed conductive circuit trace/pattern by its width (W).
squares of the resistance test strip is increased.
2.1.4 resistivity—ohms per square per mil of a conductive
material.
6. Procedure
3. Significance and Use 6.1 Pre-Test Setup:
6.1.1 Secure switch/test pattern (that is, printed and cured
3.1 Resistivity is useful to suppliers and manufacturers as
conductive material) on the test surface.
follows:
6.1.2 Measure the geometry of the test pattern as follows:
3.1.1 when designing membrane switch interface circuitry,
6.1.2.1 Measure the length (L) of the printed test pattern.
3.1.2 when selecting the appropriate conductive material,
6.1.2.2 Measure the width (W) of the printed test pattern.
3.1.3 for conductive material quality verification, and
6.1.2.3 Divide the length (L) by the width (W) to calculate
the number of squares of the printed test pattern. Should be
This test method is under the jurisdiction of Committee F01 on Electronics , $50 squares.
and is the direct responsibility of Subcommittee F01.18 on Membrane Switches.
NOTE 1—Measuring the length (L) and width (W) of the actual printed
Current edition approved May 1, 2004. Published June 2004. Originally
pattern checks the accuracy of the actual number of squares printed versus
approved in 1998. Last previous edition approved in 1998 as F1896-98. DOI:
10.1520/F1896-98R04. the artwork.
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