ASTM F2592-09

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: 14-Jun-2009
• ICS: 29.120.40 - Switches
• Technical Committee: F01 - Electronics
• Drafting Committee: F01.18 - Printed Electronics

Relations

• Replaces: ASTM F2592-08 - Standard Test Method for Measuring the Force-Displacement of a Membrane Switch
• Effective Date: 15-Jun-2009
• Replaced By: ASTM F2592-10 - Standard Test Method for Measuring the Force-Displacement of a Membrane Switch
• Effective Date: 01-Dec-2010
• Referred By: ASTM F3291-17 - Standard Test Method for Measuring the Force-Resistance of a Membrane Force Sensor (Withdrawn 2023)
• Effective Date: 15-Jun-2009
• 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: 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: 15-Jun-2009
• Referred By: ASTM F1661-09(2015) - Standard Test Method for Determining the Contact Bounce Time of a Membrane Switch
• Effective Date: 15-Jun-2009

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:F2592–09
Standard Test Method for
1
Measuring the Force-Displacement of a Membrane Switch
This standard is issued under the fixed designation F2592; 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 2.1.6 contact displacement (Tc)—the displacement at con-
tact closure.
1.1 This test method covers the measurement of force
2.1.7 contact force (Fc)—the force at contact closure.
displacement characteristics of a membrane switch.
2.1.8 displacement—measured distance of movement when
1.1.1 This test method replaces Test Method F1570 (Tactile
membrane is depressed.
Ratio). Tactile Response Slope better represents the character-
2.1.8.1 Discussion—Displacement is sometimes referred to
ization of tactile sensation, previously called “Tactile Ratio” in
as “switch travel.”
Test Method .
2.1.9 Fmax—an applied force, maximum force measured
1.1.2 This test method replaces Test Method F1682
prior to or including point (Fmin) (see Fig. 1).
(Travel).
2.1.9.1 Discussion—Sometimes referred to as Actuation
1.1.3 This test method replaces Test Method F1597 (Actua-
Force.
tion and Contact Force).
2.1.10 Fmin—an applied force, minimum force seen be-
1.1.4 This test method replaces Test Method F1997 (Switch
tween Fmax and point at which probe movement ceases.
Sensitivity).
2.1.10.1 Discussion—Fmax can equal Fmin.
1.2 Force displacement hysterisis loop curve can be used in
2.1.11 force-displacement hysteresis curve—relationship
the determination of Actuation Force, Displacement, Contact
between force applied and displacement of a membrane switch
Force, Return Force, and Tactile Response Slope.
in terms of the actuation and return (recovery).
1.3 This standard does not purport to address all of the
2.1.11.1 Discussion—Usually expressed as a line graph;
safety concerns, if any, associated with its use. It is the
sometimes referred to as Force-Travel curve (see Fig. 1).
responsibility of the user of this standard to establish appro-
2.1.12 membrane switch—a momentary switching device in
priate safety and health practices and determine the applica-
which at least one contact is on, or made of, a flexible
bility of regulatory limitations prior to use.
substrate.
2. Terminology 2.1.13 non-tactile switch—switch that does not have a
tactile response and therefore has a response slope equal to
2.1 Definitions:
zero because Fmax and Fmin are the same (see Fig. 2).
2.1.1 break displacement (Tb)—the displacement at contact
2.1.14 return min force (Frmin)—minimum force seen
break.
during return cycle before reaching Frmax.
2.1.2 break force (Fb)—the force at contact break.
2.1.15 return max force (Frmax)—maximum force mea-
2.1.3 circuit resistance—electrical resistance as measured
sured during return cycle after achieving Frmin.
between two test points whose internal contacts, when held
2.1.16 specified resistance—maximum allowable resistance
closed, complete a circuit.
as measured between two terminations whose internal switch
2.1.4 closure (make)—the event at which a specified resis-
contacts are held closed to complete a circuit.
tance is achieved.
2.1.17 switch teasing (break)—the displacement measure-
2.1.5 contact break—point at which circuit resistance is
ment on the force-displacement curve between contact break
higher than specified resistance on return.
(Fb) and return force (Frmin).
2.1.18 switch teasing (make)—the displacement measure-
1
ment on the force-displacement curve between contact force
This test method is under the jurisdiction of ASTM Committee F01 on
Electronics and is the direct responsibility of Subcommittee F01.18 on Membrane
(Fc) and minimum force (Fmin).
Switches.
2.1.19 tactile recovery slope—rate of change of return force
Current edition approved June 15, 2009. Published July 2009. Originally
with respect to displacement, as measured between TFrmin
approved in 2006. Last previous edition approved in 2008 as F2592-08. DOI:
10.1520/F2592-09. and TFrmax (see Fig. 3).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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F2592–09
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
2.1.20 tactile response—a physical sensation, caused by a 3.5 The amount of switch sensitivity or teasing can also be
sudden collapse or snapback, or both, of a membrane switch. a result of poor surface conductivity that will prevent an
2.1.21 tactile response slope—rate of
...

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:F2592–08 Designation: F 2592 – 09
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.
1.1.1 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
2.1ASTM Standards:
F1570Test Method for Determining the Tactile Ratio of a Membrane Switch
F1597
F1682Test Method for Determining Travel of a Membrane Switch
F1997Test Method for Determining the Sensitivity (Teasing) of a Tactile Membrane Switch
3.Terminology
3.1
2.1 Definitions:
3.1.1
2.1.1 break displacement (Tb)—the displacement at contact break.
3.1.2
2.1.2 break force (Fb)—the force at contact break.
3.1.3
2.1.3 circuit resistance—electrical resistance as measured between two test points whose internal contacts, when held closed,
complete a circuit.
3.1.4
2.1.4 closure (make)—the event at which a specified resistance is achieved.
3.1.5
2.1.5 contact break—point at which circuit resistance is higher than specified resistance on return.
3.1.6
2.1.6 contact displacement (Tc)—the displacement at contact closure.
3.1.7
2.1.7 contact force (Fc)—the force at contact closure.
3.1.8
2.1.8 displacement—displacement is sometimes referred to as “switch travel.”
3.1.9—measured distance of movement when membrane is depressed.
2.1.8.1 Discussion—Displacement is sometimes referred to as “switch travel.”
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. Originally approved in 2006. Last previous edition approved in 2007 as F2592-07a.
Current edition approved June 15, 2009. Published July 2009. Originally approved in 2006. Last previous edition approved in 2008 as F 2592-08.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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F2592–09
2.1.9 Fmax—an applied force, maximum force measured prior to or including point ( Fmin) (see Fig. 1).
3.1.9.1
2.1.9.1 Discussion—Sometimes referred to as Actuation Force.
3.1.10
2.1.10 Fmin—an applied force, minimum force seen between Fmax and point at which probe movement ceases.
3.1.10.1
2.1.10.1 Discussion—Fmax can equal Fmin.
3.1.11
2.1.11 force-displacement hysteresis curve—relationship between force applied and displacement of a membrane switch in
terms of the actuation and return (recovery).
3.1.11.1
2.1.11.1 Discussion—Usually expressed as a line graph; sometimes referred to as Force-Travel curve (see Fig. 1).
3.1.12
2.1.12 membrane switch—a momentary switching device in which at least one contact is on, or made of, a flexible substrate.
3.1.13
2.1.13 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).
3.1.14
2.1.14 return min force (Frmin)—minimum force seen during return cycle before reaching Frmax.
3.1.15
2.1.15 return max force (Frmax)—maximum force measured during return cycle after achieving Frmin.
3.1.16
2.1.16 specified resistance—maximum allowable resistance as measured between two terminations whose internal switch
contacts are held closed to complete a circuit.
3.
...