1、Designation: F 1995 00 (Reapproved 2005)Standard Test Method forDetermining the Bond Strength of a Surface Mount Device(SMD) on a Membrane Switch by Applying Shear Force1This standard is issued under the fixed designation F 1995; the number immediately following the designation indicates the year of
2、original adoption or, in the case of revision, the year of 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 the determination of the shearinte
3、grity of materials and procedures used to attach surfacemount devices (SMD) to a membrane switch circuit.1.2 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
4、 health practices and determine the applica-bility of regulatory limitations prior to use.2. Terminology2.1 Definitions:2.1.1 membrane switchA momentary switching device inwhich at least one contact is on (or made of) a flexiblesubstrate.2.1.2 shear loadA force applied parallel to the mountingsurfac
5、e sufficient to shear the SMD from its mounting.2.1.3 SMDAbbreviation for surface mount device (that is,light emitting diode (LED), resistor)2.1.4 attachment mediaA mounting adhesive used forelectrical or mechanical bonding, or both, of the SMD to thesubstrate.2.1.5 platingA thin metallic coating (t
6、hat is, gold, nickel)covering the leads of the SMD or circuit, or both, in theelectrical interface area.3. Significance and Use3.1 The different combinations of SMD types, attachmentmedias, circuit substrates, plating options, and process varia-tion can account for significant variation in test outc
7、ome.3.2 The SMD shear strength test is useful to manufacturersand users for determining the bond strength of the componentto the membrane switch circuit.4. Interferences4.1 The following parameters may affect the results of thistest:4.1.1 Temperature and humidity, and4.1.2 Substrate movement during
8、test.5. Apparatus5.1 Device, shall consist of a load-applying instrument withan accuracy of 6 5 % of full scale capable of indicating peakhold.5.2 Mounting Fixture, method to secure specimen to insurestability during test.5.3 SMD Contact Tool, suitable to apply a uniform distri-bution of force to an
9、 edge of the SMD.5.4 Magnification Device, suitable to facilitate visual obser-vation of the SMD and contact tool interface during testing(optional).6. Procedure6.1 Pretest Setup:6.1.1 Attach specimen to the test base to minimize move-ment of the substrate during test. Ensure that no damage occursdu
10、ring attachment to the test base that could affect bondperformance.6.1.2 The direction of applied force shall be parallel with theplane of the circuit substrate.6.1.3 The SMD contact tool shall load against an edge of thecomponent, which most closely approximates a 90 angle withthe base of the circu
11、it substrate. Contact tool should makecontact to SMD at a point equal to or less than12 the total SMDheight, (see Fig. 1).6.2 In-Process Test:6.2.1 Bring contact tool into contact with SMD specimen.6.2.2 Gradually increase force, not to exceed 225 g/s, untilbond failure.6.2.3 After initial contact w
12、ith the SMD edge and during theapplication of force, the relative position of the contact toolshall not move such that contact is made with the circuit planeor SMD attachment media. If the tool rides over the SMD, anew specimen shall be substituted.6.2.4 Record force measured to shear SMD.7. Report7
13、.1 Report the following information:7.1.1 Temperature.7.1.2 Humidity.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 May 1, 2005. Published June 2005. Originallyapp
14、roved in 1999. Last previous edition approved in 2000 as F 199500.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7.1.3 Shape and size of contact tool.7.1.4 Orientation of SMD to contact tool.7.1.5 SMD information: SMD part number, p
15、lating type,etc.7.1.6 Circuit or substrate type.7.1.7 Attachment media type.7.1.8 Force applied by contact tool when bond failureoccured.7.1.9 SMD size.7.1.10 Type of encapsulent used.8. Precision and Bias8.1 The precision and bias of this test are under investiga-tion.9. Keywords9.1 adhesion; bond
16、strength; LED; membrane switch; shearforce; SMD; surface mountASTM 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 that determination of the validity of any such
17、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 reapproved or withdrawn. Your comments are invited
18、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 you feel that your comments have not received a fa
19、ir 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 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).FIG. 1 SMD ContactF 1995 00 (2005)2
