1、Designation: F 1596 07Standard Test Method forExposure of Membrane Switches to Temperature andRelative Humidity1This standard is issued under the fixed designation F 1596; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、 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 a procedure for temperature andhumidity cycling of membrane switches.1.2 This test method is
3、 performed to evaluate the propertiesof materials used in the construction of membrane switchassemblies as they are influenced by the absorption anddiffusion of moisture and moisture vapor. This is an acceleratedenvironmental test, accomplished by the continuous exposureof the test specimen to high
4、relative humidity at an elevatedtemperature. Absorption of moisture by many materials resultsin swelling, which destroys their functional utility, causes lossof physical strength, and changes in other mechanical proper-ties. Insulating materials which absorb moisture may sufferdegradation of their e
5、lectrical properties.1.2.1 Physical changes:1.2.1.1 Differential contraction or expansion rates or in-duced strain of dissimilar materials.1.2.1.2 Cracking of surface coatings.1.2.1.3 Leaking of sealed compartments.1.2.1.4 Deformation or fracture of components.1.2.2 Chemical changes:1.2.2.1 Separati
6、on of constituents.1.2.2.2 Failure of chemical agent protection.1.2.3 Electrical changes:1.2.3.1 Changes in electronic and electrical components.1.2.3.2 Electronic or mechanical failures due to rapid waterof condensate formation.1.2.3.3 Excessive static electricity.1.3 This test method is not intend
7、ed to be a thermal shockprocedure; a ramp rate between temperature extremes shouldnot exceed 2C/min.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 heal
8、th practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2F 1661 Test Method for Determining the Contact BounceTime of a Membrane SwitchF 1662 Test Method for Verifying the Specified DielectricWithstand Voltage and Determining the
9、 Dielectric Break-down Voltage of a Membrane SwitchF 1663 Test Method for Determining the Capacitance of aMembrane SwitchF 1680 Test Method for Determining Circuit Resistance of aMembrane SwitchF 1689 Test Method for Determining the Insulation Resis-tance of a Membrane SwitchF 2592 Test Method for M
10、easuring the Force-Displacementof a Membrane Switch3. Terminology3.1 Definition:3.1.1 membrane switcha momentary switching device inwhich at least one contact is on, or made of, a flexiblesubstrate.4. Significance and Use4.1 Changes in temperature and humidity during shipping,storage or use can affe
11、ct the visual appearance, mechanicalintegrity, or electrical functionality of switches. This practicesimulates three different environments to which membraneswitches may be exposed.4.2 The three industry-recognized switch categories basedon performance levels are Level 1, Level 2, and Level 3 (seese
12、ction 8.1).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 Dec. 1, 2007. Published December 2007. Originallyapproved in 1995. Last previous edition approved in 2005 as
13、 F 159600 (2005).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.1Copyright ASTM International, 100 Barr Harb
14、or Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.3 Additionally, there may be custom requirements thatvary by application, therefore, these requirements can bedetermined by customer and vendor agreement and be estab-lished as a Level 4.4.4 This practice defines the duration o
15、f a single cycle.Multiple cycles may be appropriate depending on the require-ments of the application.5. Apparatus5.1 Closed system, with temperature and humidity control.35.2 The formation of condensation during rising tempera-ture cycles is acceptable; the formation of ice during lowtemperature cy
16、cling is not acceptable.6. Test Specimens6.1 The specimens shall be finished switches as deliveredand mounted to an actual or agreed upon substrate.7. Conditioning7.1 Condition all specimens for 72 h at 20 to 25C (68 to77F) and 20 to 80 % relative humidity (RH) immediately priorto exposure, or prior
17、 to temperature and humidity cycling. Thisis to enable the specimens to stabilize.8. Procedure8.1 Subject the preconditioned specimens to the exposuretest cycle as illustrated in Table 1.8.2 Return to room temperature and prepare for evaluation.9. Report9.1 Report the following information:9.1.1 Vis
18、ual Changes.9.1.2 Mechanical Changes.9.1.2.1 Force displacement (Test Method F 2592).9.1.2.2 Contact Bounce Time Make relative humidity (RH); temperature3A closed system such as a Tenney T3ORC, Despatch EC 619, or Espec EMX,available from Tenney, Inc., Union, NJ 07083; Despatch Industries, Minneapol
19、is,MN 55440-1320; ESPEC Corp., Grand Rapids, MI 49509, have been foundsatisfactory for this purpose.F 1596 072ASTM 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
20、 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 subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either rea
21、pproved or withdrawn. Your comments are 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 yo
22、u 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 standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual
23、 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).TABLE 1 Exposure Test CycleLevel 1 40C (40F) to 85C(185F)Level 2 25C (1
24、3F) to 70C(158F)72 h at 85C (185F)Adry heat 72 h at 70C (158F)A24 h at 38C (100F)Aand 95 % RHB24 h at 38C (100F)Aand 95 % RHB8 h at 40C (40F) 8 h at 25C (13F)A40 h at 85C (185F)Adry heat 40 h at 70C (158F)A24 h at 38C (100F)Aand 95 % RHB24 h at 38C (100F)Aand 95 % RHB72 h at 40C (40F)Adry heat 72 h
25、at 25C (13F)ALevel 3 10C (14F) to 55C (131F) Level 4 (Custom Requirement)72 h at 55C (131F)ASee 4.324 h at 38C (100F)Aand 95 % RHA8 h at 10C (14F)A40 h at 55C (131F)A24 h at 38C (100F)Aand 95 % RHA72 h at 10C (14F)AATesting to be performed in non-condensing manner unless otherwise specified.BPlace these samples in a rack at a 45 angle to allow condensate to drain from samples and arrange to allow adequate air flow between samples.F 1596 073
