ASTM F2592-08

Standard Test Method for Measuring the Force-Displacement of a Membrane Switch

SIGNIFICANCE AND USE
The force and displacement values when converted to a slope are useful in quantifying the differences in tactile response among membrane switches.
Specified resistance is useful to manufacturers and users when designing membrane switch interface circuitry.
Actuation force and contact force are useful to manufacturers and users in determining the suitability, reference and aesthetics of a membrane switch in a given application.
The tendency of a switch to make or break electrical contact at unexpected moments during closure or release can be a sign of a poor design. The degree of teasing can range from a simple annoyance to a failure of critical control process.
The amount of switch sensitivity or teasing can also be a result of poor surface conductivity that will prevent an electrical event even when switch poles are in partial contact.
SCOPE
1.1 This test method covers the measurement of force displacement characteristics of a membrane switch.
1.1.1 This test method replaces Test Method F 1570 (Tactile Ratio). Tactile Response Slope better represents the characterization of tactile sensation, previously called “Tactile Ratio” in Test Method F 1570.
1.1.2 This test method replaces Test Method F 1682 (Travel).
1.1.3 This test method replaces Test Method F 1597 (Actuation and Contact Force).
1.1.4 This test method replaces Test Method F 1997 (Switch Sensitivity).
1.2 Force displacement hysterisis loop curve can be used in the determination of Actuation Force, Displacement, Contact Force, Return Force, and Tactile Response Slope.
1.3 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: 31-Oct-2008
• ICS: 29.120.40 - Switches
• Technical Committee: F01 - Electronics
• Drafting Committee: F01.18 - Printed Electronics

Relations

• Replaces: ASTM F2592-07a - Standard Test Method for Measuring the Force-Displacement of a Membrane Switch
• Effective Date: 01-Nov-2008
• Replaced By: ASTM F2592-09 - Standard Test Method for Measuring the Force-Displacement of a Membrane Switch
• Effective Date: 15-Jun-2009
• Referred By: ASTM F1596-15 - Standard Test Method for Exposure of a Membrane Switch or Printed Electronic Device to Temperature and Relative Humidity
• Effective Date: 01-Nov-2008
• Referred By: ASTM F2865-13(2021) - Standard Guide for Classifying the Degrees of Ingress of Dust and Water into a Membrane Switch (Withdrawn 2023)
• Effective Date: 01-Nov-2008
• Referred By: ASTM F1661-09(2015) - Standard Test Method for Determining the Contact Bounce Time of a Membrane Switch
• Effective Date: 01-Nov-2008
• Referred By: ASTM F3291-17 - Standard Test Method for Measuring the Force-Resistance of a Membrane Force Sensor (Withdrawn 2023)
• Effective Date: 01-Nov-2008

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:F2592–08
Standard Test Method for
1
Measuring the Force-Displacement of a Membrane Switch
This standard is issued under the fixed designation F 2592; 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 3.1.1 break displacement (Tb)—the displacement at contact
break.
1.1 This test method covers the measurement of force
3.1.2 break force (Fb)—the force at contact break.
displacement characteristics of a membrane switch.
3.1.3 circuit resistance—electrical resistance as measured
1.1.1 This test method replacesTest Method F 1570 (Tactile
between two test points whose internal contacts, when held
Ratio). Tactile Response Slope better represents the character-
closed, complete a circuit.
ization of tactile sensation, previously called “Tactile Ratio” in
3.1.4 closure (make)—the event at which a specified resis-
Test Method F 1570.
tance is achieved.
1.1.2 This test method replaces Test Method F 1682
3.1.5 contact break—point at which circuit resistance is
(Travel).
higher than specified resistance on return.
1.1.3 This test method replaces Test Method F 1597 (Ac-
3.1.6 contact displacement (Tc)—the displacement at con-
tuation and Contact Force).
tact closure.
1.1.4 This test method replacesTest Method F 1997 (Switch
3.1.7 contact force (Fc)—the force at contact closure.
Sensitivity).
3.1.8 displacement—displacement is sometimes referred to
1.2 Force displacement hysterisis loop curve can be used in
as “switch travel.”
the determination of Actuation Force, Displacement, Contact
3.1.9 Fmax—an applied force, maximum force measured
Force, Return Force, and Tactile Response Slope.
prior to or including point (Fmin) (see Fig. 1).
1.3 This standard does not purport to address all of the
3.1.9.1 Discussion—Sometimes referred to as Actuation
safety concerns, if any, associated with its use. It is the
Force.
responsibility of the user of this standard to establish appro-
3.1.10 Fmin—an applied force, minimum force seen be-
priate safety and health practices and determine the applica-
tween Fmax and point at which probe movement ceases.
bility of regulatory limitations prior to use.
3.1.10.1 Discussion—Fmax can equal Fmin.
2. Referenced Documents 3.1.11 force-displacement hysteresis curve—relationship
between force applied and displacement of a membrane switch
2.1 ASTM Standards:
in terms of the actuation and return (recovery).
F 1570 Test Method for Determining the Tactile Ratio of a
2
3.1.11.1 Discussion—Usually expressed as a line graph;
Membrane Switch
sometimes referred to as Force-Travel curve (see Fig. 1).
F 1597 Test Method for Determining the Actuation Force
3.1.12 membrane switch—a momentary switching device in
and Contact Force of a Membrane Switch
which at least one contact is on, or made of, a flexible
F 1682 Test Method for DeterminingTravel of a Membrane
substrate.
Switch
3.1.13 non-tactile switch—switch that does not have a
F 1997 Test Method for Determining the Sensitivity (Teas-
tactile response and therefore has a response slope equal to
ing) of a Tactile Membrane Switch
zero because Fmax and Fmin are the same (see Fig. 2).
3. Terminology
3.1.14 return min force (Frmin)—minimum force seen
during return cycle before reaching Frmax.
3.1 Definitions:
3.1.15 return max force (Frmax)—maximum force mea-
sured during return cycle after achieving Frmin.
1 3.1.16 specified resistance—maximum allowable resistance
This test method is under the jurisdiction of ASTM Committee F01 on
as measured between two terminations whose internal switch
Electronics and is the direct responsibility of Subcommittee F01.18 on Membrane
Switches.
contacts are held closed to complete a circuit.
Current edition approved Nov. 1, 2008. Published December 2008. Originally
3.1.17 switch teasing (break)—the displacement measure-
approved in 2006. Last previous edition approved in 2007 as F 2592-07a.
2 ment on the force-displacement curve between contact break
Withdrawn. The last approved version of this historical standard is referenced
on www.astm.org. (Fb) and return force (Frmin).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

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F2592–08
NOTE—Area between forward and return curves is the difference in work by the tactile mechanism showing hysterisis in the tactile system.
FIG. 1 Force Displacement Hysterisis Loop
3.1.18 switch teasing (make)—the displacement measure- 4.3 Actuation force and contact force are useful to manu-
ment on the force-displacement curve between contact force facturers
...

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:F2592–07a Designation: F 2592 – 08
Standard Test Method for
1
Measuring the Force-Displacement of a Membrane Switch
This standard is issued under the fixed designation F 2592; 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 measurement of force displacement characteristics of a membrane switch.
1.1.1This test method replacesTest Method F1570.TheTactile Response Slope has been determined to be a more representative
characterization of a tactile sensation.
1.1.2This test method replaces Test Method F1682.
1.1.3This test method replaces Test Method F1597.
1.1.4This test method replaces Test Method F1997.
1.1.1 This test method replaces Test Method F 1570 (Tactile Ratio). Tactile Response Slope better represents the characteriza-
tion of tactile sensation, previously called “Tactile Ratio” in Test Method F 1570.
1.1.2 This test method replaces Test Method F 1682 (Travel).
1.1.3 This test method replaces Test Method F 1597 (Actuation and Contact Force).
1.1.4 This test method replaces Test Method F 1997 (Switch Sensitivity).
1.2 Force displacement hysterisis loop curve can be used in the determination ofActuation Force, Displacement, Contact Force,
Return Force, and Tactile Response Slope.
1.3 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. Referenced Documents
2.1 ASTM Standards:
F 1570 Test Method for Determining the Tactile Ratio of a Membrane Switch
F 1597 Test Method for Determining the Actuation Force and Contact Force of a Membrane Switch
F 1682 Test Method for Determining Travel of a Membrane Switch
F 1997 Test Method for Determining the Sensitivity (Teasing) of a Tactile Membrane Switch
3. Terminology
2.1
3.1 Definitions:
2.1.1
3.1.1 break displacement (Tb)—the displacement at contact break.
2.1.2
3.1.2 break force (Fb)—the force at contact break.
2.1.3
3.1.3 circuit resistance—electrical resistance as measured between two test points whose internal contacts, when held closed,
complete a circuit.
2.1.4
3.1.4 closure (make)—the event at which a specified resistance is achieved.
2.1.5
3.1.5 contact break—point at which circuit resistance is higher than specified resistance on return.
2.1.6
3.1.6 contact displacement (Tc)—the displacement at contact closure.
2.1.7
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 JulyNov. 1, 2007.2008. Published August 2007.December 2008. Originally approved in 2006. Last previous edition approved in 2007 as
F 2592-07a.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

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F2592–08
3.1.7 contact force (Fc)—the force at contact closure.
2.1.8
3.1.8 displacement—measured distance of movement when a membrane switch is depressed.
2.1.9—displacement is sometimes referred to as “switch travel.”
3.1.9 Fmax—an applied force, maximum force measured prior to or including point ( Fmin) (see Fig. 1).
2.1.9.1
3.1.9.1 Discussion—Sometimes referred to as Actuation Force.
2.1.10
3.1.10 Fmin—an applied force, minimum force seen between Fmax and point at which probe movement ceases.
2.1.10.1
3.1.10.1 Discussion—Fmax can equal Fmin.
2.1.11
3.1.11 force-displacement hysteresis curve—relationship between force applied and displacement of a membrane switch in
terms of the actuation and return (recovery).
2.1.11.1
3.1.11.1 Discussion—Usually expressed as a line graph; sometimes referred to as Force-Travel curve (see Fig. 1).
2.1.12
3.1.12 membrane switch—a momentary switching device in which at least one contact is on, or made of, a flexible substrate.
2.1.13
3.1.13 non-tactile switch—switch that does not have a tactile response and therefore has a response slope equal to zero because
Fmax and Fmin are the same (see Fig. 2).
2.1.14
3.1.14 return min force (Frmin)—minimum force seen during return cycle before reaching Frmax.
2.1.15
3.1.15 return max force (Frmax)—maximum force mea
...