ASTM_F_1578_-_07_2014.pdf

Designation:F157807(Reapproved 2014)Standard Test Method forContact Closure Cycling of a Membrane Switch1This standard is issued under the fixed designation F1578;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the setup,procedure,andapparatus required to depress and release a membrane switch toa predetermined number of cycles.1.2 This test method also covers the optional use of speci-fied voltage and current during the cycling of the membraneswitch.1.3 This test method can be used in conjunction with otherASTM standards such as Test Method F1596.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D2240 Test Method for Rubber PropertyDurometer Hard-nessF1596 Test Method for Exposure of Membrane Switches toTemperature and Relative HumidityF1661 Test Method for Determining the Contact BounceTime of a Membrane SwitchF1662 Test Method for Verifying the Specified DielectricWithstand Voltage and Determining the Dielectric Break-down Voltage of a Membrane SwitchF1689 Test Method for Determining the Insulation Resis-tance of a Membrane SwitchF1663 Test Method for Determining the Capacitance of aMembrane SwitchF1680 Test Method for Determining Circuit Resistance of aMembrane SwitchF2592 Test Method for Measuring the Force-Displacementof a Membrane Switch3.Terminology3.1 Definitions:3.1.1 contact closurethe event at which a specified resis-tance is achieved.3.1.2duty cyclethe ratio of switch closed time to totalcycle time.3.1.3 test ratethe number of depressions and releasecycles per second.3.1.4 membrane switcha momentary switching device inwhich at least one contact is on,or made of,a flexiblesubstrate.4.Significance and Use4.1 This testing is performed to determine the electricalcontact reliability under switching conditions and the physicalchanges caused by mechanical actuation of the switch assem-bly in the environments in which the assemblies operate.Evidence of deterioration,that is,cracking of substrate,domesboth metal and polyester,ink delamination,etc.,resulting fromthis test can at times be determined by visual examination.However,the effects may be more readily ascertained bymeasurements made prior to,during,and after exposure.Totalcircuit resistance,force-displacement,dielectric strength,insu-lation resistance,and capacitance are types of measurementsthat show the deleterious effects due to exposure.5.Apparatus5.1 Suitable Electronic Monitoring Device,to detect andcount contact closure at a predetermined or specified test rateand duty cycle.5.2 Surface,flat,smooth,unyielding,and larger than theswitch.5.3 Test Probes,built to either of the configurations shownin Fig.1 or Fig.2,are acceptable but must be made of an inertelastomeric material with a hardness number equivalent toA/45 65 as measured in accordance with Test Method D2240.Test probes that do not meet this criteria must be specified andrecorded fully.5.4 Device,which will cycle the probe repeatedly into andaway from the switch at a specified test rate and duty cycle,and1This test method is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.18 on MembraneSwitches.Current edition approved June 1,2014.Published June 2014.Originallyapproved in 1995.Last previous edition approved in 2007 as F1578 07.DOI:10.1520/F1578-07R14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 which is capable of providing means for counting probe cycles.The motion of the probe should be perpendicular to the planeof the switch.5.5 Power Supply,capable of supplying specified voltage orcurrent,or both,if required.6.Procedure6.1 Pretest Setup:6.1.1 Secure the switch on a test table.6.1.2 Measure the Fmax and Fc in accordance with TestMethod F2592 and any other desired characteristics of theswitch as specified in Section 7 and record.6.1.3 Position the test probe over the desired area of theswitch.6.1.4 Position the test probe until the tip is just above the topsurface of the switch without touching.6.1.5 Connect the switch terminations to the contact closuremonitoring device,and power supply,if applicable.6.1.6 Adjust the probe in the full-down position to achieve110%of Fmax or Fc(whiche