1、Designation: F3290 17Standard Guide forHandling and Application of a Membrane Switch or PrintedElectronic Device to its Final Support Structure1This standard is issued under the fixed designation F3290; the number immediately following the designation indicates the year oforiginal adoption or, in th
2、e 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 guide covers proper handling and application of aflexible circuit membrane switch
3、, or printed electronic assem-bly to its final support structure to avoid mechanical orelectrical failure.1.2 Damage of internal tactile devices or surface mountdevice (SMD) components can occur with excessive flexing orbending during lamination, repositioning, from uneven supportsurface, air entrap
4、ment, or pressing keys when unsupported.1.3 Design considerations and material selection can impactthe membrane switch or the printed electronic devices abilityto endure the mechanical stress that can occur in handling,application and use. These should be considered as early aspossible in the design
5、 phase.1.4 Recent advancements in printed electronic polymermaterials have shown increased reliability from flexing andcreasing, replacing copper flex circuits in many cases.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization es
6、tablished in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2F2749 Test Method for Determining the Effects of Creasinga M
7、embrane Switch or Printed Electronic DeviceF2750 Test Method for Determining the Effects of Bendinga Membrane Switch or Printed Electronic DeviceF3147 Test Method for Evaluating the Reliability of SurfaceMounted Device (SMD) Joints on a Flexible Circuit by aRolling Mandrel Bend3. Terminology3.1 Defi
8、nitions:3.1.1 membrane switch (MS), na momentary switchingdevice in which at least one contact is on, or made of, a flexiblesubstrate.3.1.2 printed electronic device (PED), nelectrically func-tional device manufactured primarily using an additiveprocess, with or without attached conventional or othe
9、r elec-tronic components, often in flexible format.4. Summary of Guide4.1 This guide provides recommendations or best practicesto prevent damage to membrane switches or printed electronicdevices from unsupported use or excessive stress during theapplication to the final supporting structure.5. Signi
10、ficance and Use5.1 Membrane switches or printed electronic devices aretested for function and aesthetically inspected by the manufac-turer before release to the end user. The user can unknowinglydamage the device beyond repair prior to, or during, theapplication (laminating) process.5.2 Awareness an
11、d proper techniques are essential to the enduser and this guide should be noted on all drawings, qualitycontrol documentation, and assembly instructions. Propertraining and practice must be provided to work area supervisorsand their staff.5.3 Concerning materials choice, consistency, and design inus
12、e, it is important to know what to look for and how to designfor durability and to test for or prevent potential failures, orboth.5.4 Component failure due to handling damage is one of themost common causes of customer complaints. It is the endusers responsibility to ensure that the product is not d
13、amagedduring installation5.5 In the event of component failures a comparison of pre-and post-assembly test performance may help determine thecause of failure. Even if an acceptable change is noted, it maybe the result of the unit being over stressed and the application1This test method is under the
14、jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.18 on PrintedElectronics.Current edition approved Nov. 1, 2017. Published November 2017. DOI:10.1520/F3290-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Cus
15、tomer 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 StatesThis international standard was deve
16、loped in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1process should be
17、reviewed and changed if necessary. It isimportant to determine if the change or failure is one thatshould have withstood the application process, or whether theapplication process is causing undue stress. Bend, Crease, andMandrel Testing in accordance with Test Methods F2749,F2750, and F3147 may be
18、necessary to determine the rootcause and location of failure.6. Procedure6.1 Handling During Testing before Applying to FinalSupport Structure:6.1.1 If unit to be tested includes SMD components that aresusceptible to ESD damage, use anti-static bags and wristbands. For example, some white and blue L
19、EDs are verysusceptible to ESD damage.6.1.2 Never store or operate a membrane switch or printedelectronic device outside of its specified storage or operatingtemperature and humidity ranges, or combination thereof.6.1.3 It is the responsibility of the user to manage the shelflife of the membrane swi
20、tch or printed electronic device (ortheir subcomponents, for example, adhesives) that has not beenattached to its final support structure.6.1.4 Do not actuate the switches (keys/buttons) of a mem-brane switch or printed electronic device while holding in yourhands or in an unsupported position. Actu
21、ating a membraneswitch or printed electronic device in this manner can causedamage to the switch.6.1.5 When testing, the membrane switch assembly orprinted electronic device should be positioned flat on a rigidsurface such as a table or test fixture.6.1.6 Take caution when positioning the membrane s
22、witchor printed electronic devices connector into the test device.Avoid undue mechanical stress on flex tail or connector whenattaching to test fixture.6.1.7 Do not actuate switches with a hard, pointed object(like a pen, stylus, screwdriver, etc.) as this can cause perma-nent damage. A human finger
23、 or an elastic tip actuator arerecommended for actuating switches.6.2 Application to Final Support Structure:6.2.1 The mating surface should be thoroughly clean andfree of dust/debris, lubricants, mold-release, surfactants, etc.prior to application of the membrane switch or printed elec-tronic devic
24、e. Clean if necessary using a lint-free cloth withappropriate cleaner, for example, isopropyl alcohol (IPA).Ensure that the cleaner evaporates completely prior to appli-cation of the membrane switch or printed electronic device.6.2.2 Dust and other contamination can cause witness markson the viewing
25、 surface. Lubricants, mold-release, etc. canprevent the mounting adhesive from achieving an adequatebond, causing the membrane switch or printed electronicdevice to release almost immediately or over time.6.2.3 Inspect mounting surface for convex or concavedefects which can cause undesirable switch
26、operation, as wellas cosmetic defects.6.2.4 Prior to application of the membrane switch or printedelectronic device, make sure to remove any protective maskingthat may be present on the underside of any display window.Once the membrane switch or printed electronic device ismounted, removing the mask
27、ing can prove to be difficult anddamaging to the device.6.2.5 Excessive bending or flexing of the membrane switchassembly or printed electronic device will cause internaldamage (premature failure or collapsed domes and fracturedjoints of surface mount LEDs, etc.). See Fig. 1. Refer to TestMethods F2
28、749, F2750, and F3147 to test for durability atextreme conditions and performance/compatibility of the se-lected material set for example, ink, adhesive, substrate, andSMD land design.6.2.6 When mounting the membrane switch or printedelectronic device, the choice of starting position depends onmany
29、factors and is application specific. It is typically best tostart with the side/end where the flex tail exits. If there areLEDs or switches in this area, extreme care should be taken orconsider starting in a different location. Remove a strip(approximately12 in. to34 in. wide) of the rear adhesivesr
30、elease liner and bend the liner back onto itself. Remember tocompletely remove the release liner from the tail insert piece (ifFIG. 1 Application to Final Support StructureF3290 172applicable) under the flex tail. Parts with gaskets may requireremoval of multiple pieces of adhesive liner.6.2.7 Pass
31、the flex tail through the notch or slot in themating surface and align the membrane switch or printedelectronic device properly to the surface or recess edge. Pressthe exposed adhesive area down onto the surface to set thealignment.6.2.8 Moderately bend back the membrane switch or printedelectronic
32、device and remove the remaining adhesive liner. Besure to remove all liner material.6.2.9 Starting from the pre-set tail area, with the membraneswitch or printed electronic device flat or slightly flexed,slowly apply it to the mating surface, smoothing it out as yougo to prevent any air from being t
33、rapped under the device.Trapped air can cause permanently actuated switches orwitness marks (unsightly bumps) on the viewing surface. Theadhesive is typically a permanent pressure-sensitive type andrequires firm pressure to ensure a strong bond.6.2.10 When burnishing a membrane switch or printedelec
34、tronic device to the mating surface, it is ideal to use atemplate and a suitable rubber roller (typically 40+5 shore Adurometer), applying with moderate pressure. If a template androller are not suitable for a particular application, the mem-brane switch or printed electronic device can be hand bur-
35、nished to the mating surface.6.2.11 When hand burnishing a membrane switch or printedelectronic device to the mating surface, use a finger topress/rub (with moderate pressure) over the entire surfaceexcept for switches, surface mount components such as LEDs,and display windows. Never burnish over th
36、e switches andsurface mount components (LEDs, etc.) as this could causedamage. If there are areas which cannot be accessed by afinger, a soft plastic tool with a rounded end can be used toapply pressure. The tool should have a rounded end rather thana sharp or pointed tip that will cause damage. Whe
37、n using atool to burnish, test in a small area to make sure the tool doesnot damage the surface of the device.6.2.11.1 A membrane switch or printed electronic deviceshould never be applied, removed, and then reapplied to itsmating surface. This action can cause damage to the layers,domes, or surface
38、 mount joints, or combination thereof. Referto Test Methods F2749, F2750, and F3147 to test for durabilityat extreme conditions and performance/compatibility of theselected material set for example ink, adhesive, substrate, andSMD land design.7. Keywords7.1 bending; creasing; flexing; membrane swith
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