ASTM_F_1596_-_15.pdf

Designation:F159615Standard Test Method forExposure of a Membrane Switch or Printed ElectronicDevice to Temperature and Relative Humidity1This standard is issued under the fixed designation F1596;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 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 covers a procedure for temperature andhumidity cycling of a membrane switch or printed electronicdevice.1.2 This test method is performed to evaluate the propertiesof materials used in the construction of membrane switch orprinted electronic assemblies as they are influenced by theabsorption and diffusion of moisture and moisture vapor.Thisis an accelerated environmental test,accomplished by thecontinuous exposure of the test specimen to high relativehumidity at an elevated temperature.Absorption of moisture bymany materials results in swelling,which destroys their func-tional utility,causes loss of physical strength,and changes inother mechanical properties.Insulating materials which absorbmoisture may suffer degradation of their electrical 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 Separation 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 intended 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 health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2F1595 Practice for Viewing Conditions for Visual Inspectionof Membrane SwitchesF1661 Test Method for Determining the Contact BounceTime of a Membrane SwitchF1662 Test Method for Verifying the Specified DielectricWithstand Voltage and Determining the Dielectric Break-down Voltage of a Membrane SwitchF1663 Test Method for Determining the Capacitance of aMembrane Switch or Printed Electronic DeviceF1680 Test Method for Determining Circuit Resistance of aMembrane SwitchF1689 Test Method for Determining the Insulation Resis-tance of a Membrane SwitchF2592 Test Method for Measuring the Force-Displacementof a Membrane Switch3.Terminology3.1 Definitions: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 affect 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(seesection 9.1).1This test method is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.18 on PrintedElectronics.Current edition approved June 1,2015.Published July 2015.Originally approvedin 1995.Last previous edition approved in 2007 as F159607.DOI:10.1520/F1596-15.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 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 of 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 cycling 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 to temperature and humidity cycling.Thisis to enable the specimens to