ASTM_F_2188_-_02_2011.pdf

Designation:F218802(Reapproved 2011)Standard Test Method forDetermining the Effect of Variable Frequency Vibration on aMembrane Switch or Membrane Switch Assembly1This standard is issued under the fixed designation F2188;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 establishes procedures for determiningthe effect of sinusoidal vibration,within the specified fre-quency range,on switch contacts,mounting hardware,adheredcomponent parts,solder or heat stakes,tactile devices,andcable or ribbon interconnects associated with a membraneswitch or membrane switch assembly.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.Terminology2.1 Definitions:2.1.1 contact closurethe event at which a specified resis-tance is achieved on a membrane switch.2.1.2 critical resonance frequencyany point on the speci-men that is observed to have maximum amplitude or more thantwice that of the base input amplitude or support points.2.1.3 membrane switcha momentary switching device inwhich at least one contact is on,or made of,a flexiblesubstrate.2.1.4 specified resistancemaximum allowable circuit re-sistance as measured between two test points whose internalcontacts,when held closed,complete a circuit.2.1.5 test pointstwo pre-selected conductive points in acircuit loop,possibly including a switch.3.Significance and Use3.1 Vibration encountered in the field is not usually simpleharmonic.3.2 This test can be used to determine relative motionbetween parts,critical frequencies,adhesion strengths,loosen-ing of parts or other physical effects that can cause fatigue orfailure.3.3 Experience has shown that this test will expose potentialfailures associated with the electronic components of a mem-brane switch,where tests of lower levels will not.3.4 This practice can be used to qualify a membrane switchfor aerospace,medical and other applications.3.5 This test is potentially destructive,intended for devicequalification.3.6 Either Test Condition A or B can be chosen,based uponthe intent of the test determined by the qualified engineer.4.Apparatus4.1 Vibration Fixture,capable of holding the unit under testand subjecting it to the specified random frequency andduration as described in the In-Process Test.4.2 Contact Closure Detection Device,(if test is performedunder load conditions),instrumentation capable of resolving aswitch opening time of greater than or equal to 1.0 ms.4.3 Resonant Detecting Instrumentation,(if determinationof critical resonance frequency is desired),capable of deter-mining the critical resonance frequency.5.ProcedureTest Condition A,10 g5.1 Pre-Test Setup:5.1.1 Secure membrane switch on vibration test surfacewith appropriate fixturing.5.1.2 Connect switch detection leads to test points on themembrane switch(if contact closure is being monitored duringthe test).5.1.3 Function testing to be specified and performed againafter test completion for comparison.5.2 In-Process Test:5.2.1 Subject test unit to sinusoidal vibration varied infrequency from 10 to 500 Hz at a logarithmic rate of 0.5 octaveper minute for a duration of 18 cycles per each orthogonal axis(total of 56 times).The amplitude of the vibration shall be1This 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 Feb.1,2011.Published March 2011.Originallyapproved in 2002.Last previous edition approved in 2002 as D2188-02.DOI:10.1520/F2188-02R11.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 either 0.06-in.double inch amplitude or 10 gravities(g-peak),whichever is less.The tolerance for the vibration profile is63dB.5.2.2 Visual inspection shall be conducted after each axis ofvibration.5.2.3 Electrical and functional testing shall be specified bythe qualified engineer and performed at either test completionor between each axis of vibration.5.2.4 Afailure shall occur if parts show signs of mechanicalfatigue,cracking,excessive rubbing or loosening of the sup-porting hardware.Afailure should also be designated if contactclosure occurs during vibration and or electrical or otherfunctional testing provides unsatisfactory results.6.ProcedureTest Condition B,20 g6.1 Pre-Test Setup:6.1.1 Secure membrane switch on vibration test surfacewith appropriate fixturing.6.1.2 Connect switch detection leads to test points on themembrane switch(if contact closure is being monitored duringtest).6.1.3 Function