1、Designation: F1762 07F1762 14Standard Practice Test Method forExposing a Membrane Switch to Variation in AtmosphericPressure Determining the Effects of Atmospheric PressureVariation on a Membrane Switch1This standard is issued under the fixed designation F1762; the number immediately following the d
2、esignation 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 practice test method c
3、overs a procedure for exposing a membrane switch to variations in atmospheric pressure. It canbe used to determine the effects of pressure variations on chemical and mechanical properties and functional characteristics of theswitch.2. Referenced Documents2.1 ASTM Standards:2F1595 Practice for Viewin
4、g Conditions for Visual Inspection of Membrane SwitchesF1663 Test Method for Determining the Capacitance of a Membrane SwitchF1680 Test Method for Determining Circuit Resistance of a Membrane SwitchF1689 Test Method for Determining the Insulation Resistance of a Membrane SwitchF1895 Test Method for
5、Submersion of a Membrane SwitchF2592 Test Method for Measuring the Force-Displacement of a Membrane Switch3. Terminology3.1 Definitions:3.1.1 circuit resistanceelectrical resistance as measured between two test points whose internal contacts, when held closed,complete a circuit.3.1.2 contact closure
6、the event at which a specified resistance is achieved on a membrane switch.3.1.3 membrane switcha momentary switching device in which at least one contact is on, or made of, a flexible substrate.3.1.4 specified resistancethe maximum allowable circuit resistance as measured between two test points wh
7、ose internalcontacts, when held closed, complete a circuit.3.1.5 test pointstwo preselected conductive points in a circuit loop, possibly including a switch.4. Significance and Use4.1 Erratic operation or malfunction of a membrane switch resulting from changes in the specified switch characteristics
8、,4.2 Rupture, implosion or explosion of seals due to pressure variations,4.3 Change in physical or chemical properties due to pressure differentiations, and4.4 Delaminations of a membrane switch may occur due to pressure variations.5. Interferences5.1 Time duration before, during and after pressure
9、cycling,5.2 Temperature,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 Dec. 1, 2007Jan. 1, 2014. Published December 2007January 2014. Originally approved in 1996.
10、Last previous edition approved in 20022007as F176202.07. DOI: 10.1520/F1762-07.10.1520/F1762-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Documen
11、t Summary page on the ASTM website.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. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM reco
12、mmends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.3 Humidity,
13、5.4 Mounting Method (if applicable).6. Apparatus6.1 Pressure Chamber, a chamber or cabinet capable of maintaining a specified pressure. If procedurally required, the apparatusshall be capable of providing pressure variation at a specified rate.6.2 Monitoring Device, suitable to detect contact closur
14、e (that is, ohm meter, etc.).7. Conditioning7.1 Condition all specimens for 72 h at ambient laboratory conditions 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 characteristic
15、s of the switch so that comparable measurements and observations can bemade prior to, during orand after the test. Some suggested values are:8.1.1.1 Document the setup, test equipment, and mountingCircuit resistance in accordance with Test Method F1680procedure(if applicable) used to measure the cha
16、racteristics8.1.1.2 Capacitance in accordance with Test Method F1663.8.1.1.3 Force displacement in accordance with Test Method F2592.8.1.1.4 Insulation resistance in accordance with Test Method F1689.8.1.1.5 Submersion in accordance with Test Method F1895 (for sealed switch only).8.1.1.6 Visual insp
17、ection in accordance with Test Method F1595.8.1.2 Connect predetermined switch terminations to contact closure resistance measuring device.8.2 In-Process Test:8.2.1 Place specimens in the chamber at ambient conditions, record time and date, and initiate contact closure monitoringmeasuring device.8.2
18、.2 Adjust the ramp rate to decrease air pressure at 2000 ft/min unless otherwise specified.8.2.3 Set pressure as specified.at desired level from Table 1.8.2.4 Maintain the chamber pressure for the one hour or a specified time interval.8.2.5 Return chamber pressure to the initial ambient conditions a
19、t 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 switch as in 7.1.18.1.1. Record time and date for each characteristicmeasured.9. Report9.1 Report the following information:9.1.1 Pressure level (from Table 1).9.1.
20、2 Time interval.9.1.3 Ramp rate.9.1.4 Temperature.9.1.5 Humidity.9.1.6 Change in measured or observed characteristics.9.1.7 Any self-closure events that occurred during test.10. Precision and Bias10.1 The precision and bias of this test are under investigation.TABLE 1 Pressure LevelTestConditionPres
21、sure Maximum AltitudeInches ofmercuryMillimetersof mercuryFeet MetersA 8.88 226.00 30 000 9 144B 3.44 87.00 50 000 15 240C 1.31 33.00 70 000 21 336D 0.315 8.00 100 000 30 480F1762 14211. Keywords11.1 contact closure; delamination; membrane switchASTM International takes no position respecting the va
22、lidity 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 of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is su
23、bject 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 are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headqua
24、rters. 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 received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standa
25、rd 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).F1762 143
