1、Designation: F1895 10aF1895 14Standard 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
2、 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 the submerging of a membrane switch to verify resistance to ingress of aspecified liquid.1.2 This te
3、st method can also be used to verify the ability of a membrane switch or graphics layer to act as a liquid seal for afinished product.1.3 Additional test methods or practices can be incorporated to investigate specific results or capabilities.1.4 This test method is a modification of National Electr
4、ical ManufacturersAssoc. (NEMA) Publication 250-1991 Section 6.10,which is a test for submersion of a finished product housing.1.5 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematicalconversions to SI units that are provided for infor
5、mation only and are not considered standard.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulato
6、rylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2F1595 Practice for Viewing 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 T
7、est Method for Determining the Insulation Resistance of a Membrane Switch2.2 National Electrical Manufacturers Assoc.:3(NEMA) Publication 250-19913. Terminology3.1 Definitions:3.1.1 membrane switchA momentary switching device in which at least one contact is on, or made of, a flexible substrate.3.1.
8、2 specified resistancemaximum allowable resistance as measured between two terminations whose internal switchcontacts, when held closed, complete a circuit.3.1.3 silver migrationgrowth of fine crystals between silver conductors of a thick film circuit due to an ionic reaction to thepresence of water
9、 and an applied dc voltage potential.4. Significance and Use4.1 The presence of water inside a membrane switch can affect its mechanical operation or electrical functionality, or both.Electrical failure can result as short circuits due to silver migration or exceeding the specified resistance due to
10、 oxidation.4.2 This test method establishes a procedure to verify the ability of a membrane switch to resist the entry of liquid in itself ora finished product, or both. It is useful in identifying design deficiencies.1 This test method is under the jurisdiction of ASTM Committee F01 on Electronics
11、and is the direct responsibility of Subcommittee F01.18 on Membrane Switches.Current edition approved Dec. 1, 2010Jan. 1, 2014. Published December 2010January 2014. Originally approved in 1998. Last previous edition approved in 2010 as F1895- 10.10a. DOI: 10.1520/F1895-10A.10.1520/F1895-14.2 For ref
12、erencedASTM 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 Document Summary page on the ASTM website.3 Available from National Electrical Manufacturers Association (NEMA),
13、 1300 N. 17th St., Suite 1752, Rosslyn, VA 22209, http:/www.nema.org.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
14、 all changes accurately, ASTM recommends 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
15、-2959. United States14.3 Submersion testing may be destructive, therefore any samples tested should be considered unfit for future use.5. Interferences5.1 External Ventingany deliberate external venting of the switch will allow liquid to enter.5.2 Atmospheric Pressuresignificant changes in atmospher
16、ic pressure during the test or at different facilities may alter the timein which leakage might occur.5.3 Duration of Testlonger submersion time increases the possibility of leakage.5.4 Dye Coloringchose a dye coloring that will not chemically attack the materials.6. Apparatus6.1 Tub of sufficient s
17、ize and depth (w/cover) for the entire switch, including any mounting surface to be submerged by at least1 in. (25.4 mm) or as specified.6.2 An appropriate device of fixture to hold the switch in a fixed position.6.3 Any additional equipment as required by other test methods employed.7. Test Specime
18、n7.1 The test specimens may be membrane switches with or without graphics.7.2 Laminate to specified material or to a rigid clear material (using a clear material will facilitate visual inspection).7.3 Membrane switches or graphic overlays designed to act as a liquid seal for the finished product are
19、 to be applied to a rigidmaterial.8. Conditioning8.1 Condition specimens by exposure to ambient conditions for 72 h prior to submersion to allow full cure of adhesives.8.2 Consideration should be given to mechanically conditioning the switch to simulate the stress and strain of handling andassembly.
20、9. Procedure9.1 Pre-Test Setup:9.1.1 Fixture Unit Under Test (UUT) horizontally (or as specified).specified) and perform the following tests:9.1.1.1 Measure circuit resistance in accordance with Test Method F1680 of preselected (or all) switches.9.1.1.2 Measure capacitance in accordance with Test Me
21、thod F1663 of preselected (or all) mutually isolated test points.9.1.1.3 Measure insulation resistance in accordance with Test Method F1689 of preselected (or all) conductive points.9.1.1.4 Visually inspect in accordance with Practice F1595 and note anything that could affect results or of interest
22、to compareafter test. Pictures of UUT may be useful as well but not required.9.1.2 Fill tub with specified liquid to provide a level of approximately 1 in. (25.4 mm) above the uppermost surface of UUTor as specified.9.1.3 Add dye coloring and stir for consistency (optional).Add dyed saline solution
23、and stir for consistency (other trace methodsi.e. fluroescein)9.1.4 Allow liquid bath to stabilize to ambient temperature.9.2 In-Process Test9.2.1 Test switch for proper function is required.9.2.1 Position UUT in tub using appropriate fixturing; cover tub.9.2.2 Keep UUT submerged for 24 h or as spec
24、ified.9.2.3 Remove UUT and allow to air dry.9.2.4 Test switch for proper function is required.9.2.5 Perform visual inspection to determine Test the same characteristics as performed in 9.1.1 and if liquid has penetrated theUUT.UUT record as much detail as possible the extent of penetration seen by v
25、isual inspection. Pictures of UUT may be usefulas well but not required.10. Report10.1 Report the following information:10.1.1 Bath temperature,temperature.10.1.2 Liquid usedused.10.1.3 Atmospheric PressurePressure.10.1.4 Duration of TestTest.F1895 14210.1.5 Physical/Aesthetic ChangesChanges.10.1.5.
26、1 Visual inspection (Practice F1595).10.1.5.2 Liquid penetration description.10.1.5.3 Pictures of UUT (if available).10.1.6 Functional Test Data is required.Electrical Characteristic Changes:10.1.6.1 Circuit resistance (Test Method F1680).10.1.6.2 Capacitance (Test Method F1663).10.1.6.3 Insulation
27、resistance (Test Method F1689).10.1.7 Method of mechanically conditioning, if any.11. Precision and Bias11.1 Precision and bias for non-quantitative results, such as visual changes, are not required.12. Keywords12.1 immersion; membrane switch; submersion; water immersionASTM International takes no p
28、osition 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 of any such patent rights, and the riskof infringement of such rights, are entirely their own responsib
29、ility.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 are invited either for revision of this standard or for additional standardsand should be addressed to A
30、STM 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 received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the addres
31、s 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).F1895 143
