ASTM_F_1682_-_02.pdf

Designation:F 1682 02Standard Test Method forDetermining Travel of a Membrane Switch1This standard is issued under the fixed designation F 1682;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the travelof a membrane switch.1.2 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:2F 1570 Test Method for Determining the Tactile Ratio of aMembrane Switch3.Terminology3.1 Definitions:3.1.1 circuit resistanceelectrical resistance as measuredbetween two test points whose internal contacts,when heldclosed,complete a circuit.3.1.2 contact closurethe event at which a specified resis-tance is achieved on a membrane switch.3.1.3 Fmax(actuation force)maximum force measuredprior to or including point at which contact closure(Fmin)isachieved(see Fig.1 and Fig.2).3.1.4 Fminminimum force seen between Fmaxand point atwhich probe movement ceases.Fmaxcan equal Fmin.Fminis theideal location for contact closure(see Fig.1 and Fig.2).3.1.5 membrane switcha momentary switching device inwhich at least one contact is on,or made of,a flexiblesubstrate.3.1.6 non-tactile switcha switch assembly that provides atactile ratio equal to zero(see Test Method F 1570).3.1.7 specified resistancemaximum allowable circuit re-sistance as measured between two test points whose internalcontacts,when held closed,complete a circuit.3.1.8 tactile switcha switch assembly that provides atactile ratio greater than zero(see Test Method F 1570).3.1.9 test pointstwo preselected conductive points in acircuit loop,possibly including a switch.3.1.10 traveldistance moved by the surface in contactwith the test probe.4.Significance and Use4.1 Switch travel is one factor used to quantify the feel of amembrane switch.5.Apparatus5.1 Test Probe,made of nonelastic material with shape andsize to be specified.5.2 Device,to hold probe securely and provide perpendicu-lar movement into and away from switch under test.5.3 Monitoring Device,suitable to detect Fmaxand Fmin.1This 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 Jan.10 2002.Published March 2002.Originallypublished as F 168296.Last previous edition F 168296.2For 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.FIG.1 Typical Tactile ForceTravel Curve1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.5.4 Test Surface,flat,smooth,unyielding and larger thanswitch under test.5.5 Suitable Monitoring Device,to measure travel.6.Procedure6.1 PreTest Setup:6.1.1 Determine if switch is“tactile”or“non-tactile”.Ifunknown,measure in accordance with Test Method F 1570(see Fig.1 and Fig.2).6.1.2 Precondition switch by depressing manually 25 times.6.1.3 Secure switch on test surface.6.1.4 Position test probe over desired area of switch.6.1.5 Attach travel monitoring device to probe.6.1.6 Position probe until tip is just touching top surface ofswitch.6.1.7 Set travel monitoring device to zero.6.2 In-Process Test,Tactile Switch(Tactile Ratio 0)(seeFig.1):6.2.1 Begin by activating test probe movement down at arate not to exceed 13 mm/s.6.2.2 Continue probe movement past Fmaxuntil reachingFmin(see Fig.1),record travel.6.2.3 Reverse direction of test probe until it is no longertouching the top surface of the switch.6.2.4 Repeat 6.2.1 thru 6.2.3 four times.6.3 In-Process Test,Non-Tactile Switch(Tactile Ratio=0)(see Fig.2):6.3.1 Begin by activating test probe movement down at arate not to exceed 13 mm/s.6.3.2 Continuetraveluntilprobemovementstops(Fmax=Fmin;see Fig.2),record travel.6.3.3 Reverse direction of test probe until it is no longertouching the top surface of the switch.6.3.4 Repeat 6.3.1 thru 6.3.3 four times.7.Calculations7.1 Determine the average of five readings and record as“Travel.”8.Report8.1 Report the following information:8.1.1 Temperature,8.1.2 Relative humidity,8.1.3 Barometric pressure,8.1.4 Shape and size of probe,8.1.5 Description of probe holding fixture and monitoringdevice,8.1.6 Part number or description of switch,or both,8.1.7 Date of test,and8.1.8 Travel.9.Precision and Bias9.1 The precision and bias of this test method are underinvestigation.10.Keywords10.1 displacement;membrane switch;travelAS