ASTM F1895-2010a Practice for Submersion of a Membrane Switch《膜片式开关浸渍的操作规程》.pdf

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1、Designation: F1895 10aStandard Test Method forSubmersion of a Membrane Switch1This standard is issued under the fixed designation F1895; 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 parenth

2、eses 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 the sub-merging of a membrane switch to verify resistance to ingress ofa specified liquid.1.2 This test meth

3、od can also be used to verify the ability ofa membrane switch or graphics layer to act as a liquid seal fora finished product.1.3 Additional test methods or practices can be incorporatedto investigate specific results or capabilities.1.4 This test method is a modification of National ElectricalManuf

4、acturers Assoc. (NEMA) Publication 250-1991 Section6.10, which is a test for submersion of a finished producthousing.1.5 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information only

5、and are not considered standard.1.6 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 limitati

6、ons prior to use.2. Referenced Documents2.1 National Electrical Manufacturers Assoc.:2(NEMA) Publication 250-19913. Terminology3.1 Definitions:3.1.1 membrane switchA momentary switching device inwhich at least one contact is on, or made of, a flexiblesubstrate.3.1.2 specified resistancemaximum allow

7、able resistanceas measured between two terminations whose internal switchcontacts, when held closed, complete a circuit.3.1.3 silver migrationgrowth of fine crystals betweensilver conductors of a thick film circuit due to an ionic reactionto the presence of water and an applied dc voltage potential.

8、4. Significance and Use4.1 The presence of water inside a membrane switch canaffect its mechanical operation or electrical functionality, orboth. Electrical failure can result as short circuits due to silvermigration or exceeding the specified resistance due to oxida-tion.4.2 This test method establ

9、ishes a procedure to verify theability of a membrane switch to resist the entry of liquid initself or a finished product, or both. It is useful in identifyingdesign deficiencies.4.3 Submersion testing may be destructive, therefore anysamples tested should be considered unfit for future use.5. Interf

10、erences5.1 External Ventingany deliberate external venting of theswitch will allow liquid to enter.5.2 Atmospheric Pressuresignificant changes in atmo-spheric pressure during the test or at different facilities mayalter the time in which leakage might occur.5.3 Duration of Testlonger submersion time

11、 increases thepossibility of leakage.5.4 Dye Coloringchose a dye coloring that will notchemically attack the materials.6. Apparatus6.1 Tub of sufficient size and depth (w/cover) for the entireswitch, including any mounting surface to be submerged by atleast 1 in. (25.4 mm) or as specified.6.2 An app

12、ropriate device of fixture to hold the switch in afixed position.6.3 Any additional equipment as required by other testmethods employed.7. Test Specimen7.1 The test specimens may be membrane switches with orwithout graphics.7.2 Laminate to specified material or to a rigid clearmaterial (using a clea

13、r material will facilitate visual inspec-tion).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, 2010. Published December 2010. Originallyapproved in 1998. Last

14、previous edition approved in 2010 as F1895 - 10. DOI:10.1520/F1895-10A.2Available from National Electrical Manufacturers Association (NEMA), 1300N. 17th St., Suite 1752, Rosslyn, VA 22209, http:/www.nema.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 194

15、28-2959, United States.7.3 Membrane switches or graphic overlays designed to actas a liquid seal for the finished product are to be applied to arigid material.8. Conditioning8.1 Condition specimens by exposure to ambient conditionsfor 72 h prior to submersion to allow full cure of adhesives.8.2 Cons

16、ideration should be given to mechanically condi-tioning the switch to simulate the stress and strain of handlingand assembly.9. Procedure9.1 Pre-Test Setup:9.1.1 Fixture Unit Under Test (UUT) horizontally (or asspecified).9.1.2 Fill tub with specified liquid to provide a level ofapproximately 1 in.

17、(25.4 mm) above the uppermost surface ofUUT or as specified.9.1.3 Add dye coloring and stir for consistency (optional).Add dyed saline solution and stir for consistency (other tracemethods i.e. fluroescein)9.1.4 Allow liquid bath to stabilize to ambient temperature.9.2 In-Process Test9.2.1 Test swit

18、ch for proper function is required.9.2.2 Position UUT in tub using appropriate fixturing; covertub.9.2.3 Keep UUT submerged for 24 h or as specified.9.2.4 Remove UUT and allow to air dry.9.2.5 Test switch for proper function is required.9.2.6 Perform visual inspection to determine if liquid haspenet

19、rated the UUT.10. Report10.1 Report the following information:10.1.1 Bath temperature,10.1.2 Liquid used10.1.3 Atmospheric Pressure10.1.4 Duration of Test10.1.5 Physical/Aesthetic Changes10.1.6 Functional Test Data is required.10.1.7 Method of mechanically conditioning, if any.11. Precision and Bias

20、11.1 Precision and bias for non-quantitative results, such asvisual changes, are not required.12. Keywords12.1 immersion; membrane switch; submersion; waterimmersionASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this

21、 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 subject to revision at any time by the responsible technical committee and must be

22、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 Headquarters. Your comments will receive careful consideration at a meeting of therespo

23、nsible 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 standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, Wes

24、t 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/).F1895 10a2