1、Designation: F 1762 02Standard Practice forExposing a Membrane Switch to Variation in AtmosphericPressure1This standard is issued under the fixed designation F 1762; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、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 practice covers a procedure for exposing a mem-brane switch to variations in atmospheric pressure. It can beused to d
3、etermine the effects of pressure variations on chemicaland mechanical properties and functional characteristics of theswitch.2. Referenced Documents2.1 ASTM Standards:2F 1570 Test Method for Determining the Tactile Ratio of aMembrane SwitchF 1597 Test Method for Determining the Actuation Forceand Co
4、ntact Force of a Membrane 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
5、.3.1.3 membrane switcha momentary switching device inwhich at least one contact is on, or made of, a flexiblesubstrate.3.1.4 specified resistancethe maximum allowable circuitresistance as measured between two test points whose internalcontacts, when held closed, complete a circuit.3.1.5 test pointst
6、wo preselected conductive points in acircuit loop, possibly including a switch.4. Significance and Use4.1 Erratic operation or malfunction of a membrane switchresulting from changes in the specified switch characteristics,4.2 Rupture, implosion or explosion of seals due to pressurevariations,4.3 Cha
7、nge in physical or chemical properties due to pres-sure differentiations, and4.4 Delaminations of a membrane switch may occur due topressure variations.5. Interferences5.1 Time duration before, during and after pressure cycling,5.2 Temperature,5.3 Humidity,5.4 Mounting Method (if applicable).6. Appa
8、ratus6.1 Pressure Chamber, a chamber or cabinet capable ofmaintaining a specified pressure. If procedurally required, theapparatus shall be capable of providing pressure variation at aspecified rate.6.2 Monitoring Device, suitable to detect contact closure(that is, ohm meter, etc.).7. Conditioning7.
9、1 Condition all specimens for 72 h at ambient laboratoryconditions immediately prior to exposure, or prior to pressurecycling. This is to enable the specimens to stabilize.8. Procedure8.1 Pretest Setup:8.1.1 Measure or observe the desired characteristics of theswitch so that comparable measurements
10、and observations canbe made during or after the test.8.1.1.1 Document the setup, test equipment, and mountingprocedure (if applicable) used to measure the characteristics.8.1.2 Connect predetermined switch terminations to contactclosure measuring device.8.2 In-Process Test:1This test method is under
11、 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 176296. Last previous editon F 176297.2For referenced ASTM standards, visit the AST
12、M 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, Unite
13、d States.8.2.1 Place specimens in the chamber at ambient conditions,record time and date, and initiate contact closure monitoringdevice.8.2.2 Adjust the ramp rate to decrease air pressure at 2000ft/min unless otherwise specified.8.2.3 Set pressure as specified.8.2.4 Maintain the chamber pressure for
14、 the specified timeinterval.8.2.5 Return chamber pressure to the initial ambient condi-tions at the specified rate.8.2.6 Remove specimens and record time and date.8.3 Post Test:8.3.1 Measure and observe the characteristics of the switchas in 8.1.1. Record time and date for each characteristicmeasure
15、d.8.4 For determining the tactile ratio of a membrane switch,test in accordance with Test Method F 1570.8.5 For detemining the actuation force and contact force ofa membrane switch, test in accordance with Test Method F1597.9. Precision and Bias9.1 The precision and bias of this test are under inves
16、tiga-tion.10. Keywords10.1 contact closure; delamination; membrane switchASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity o
17、f any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments a
18、re invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not re
19、ceived a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).F 1762 022
