1、Designation:F199512F199513 Standard Test Method for Determining the Shear Force of Strength of the Bond between a Surface Mount Device (SMD) and Substrate in a Membrane Switch 1 This standard is issued under the xed designation F1995; the number immediately following the designation indicates the ye
2、ar of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval. 1. Scope 1.1 This test method covers the determination of the s
3、hear integrity of materials and procedures used to attach surface mount devices (SMD) to a membrane switch circuit. 1.2 This test method is typically used to indicate the sufficient cure of conductive adhesive or underll, or both. In general, this test method should be used prior to encapsulant. Thi
4、s test may also be used to demonstrate the Shear Force with encapsulation. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with
5、its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Terminology 2.1 Denitions: 2.1.1 membrane switchA momentary switching device in which at least one contact is
6、 on (or made of) a exible substrate. 2.1.2 shear loadA force applied parallel to the mounting surface sufficient to shear the SMD from its mounting. 2.1.3 SMDAbbreviation for surface mount device (for example, light emitting diode (LED), resistor) 2.1.4 attachment mediaAmounting adhesive used for el
7、ectrical or mechanical bonding, or both, of the SMD to the substrate. 2.1.5 platingAthin metallic coating (that is, gold, nickel) covering the leads of the SMD or circuit, or both, in the electrical interface area. 3. Signicance and Use 3.1 The different combinations of SMD types, attachment medias,
8、 circuit substrates, plating options, and process variation can account for signicant variation in test outcome. 3.2 The SMD shear strength test is useful to manufacturers and users for determining the bond strength of the component to the membrane switch circuit. 4. Interferences 4.1 The following
9、parameters may affect the results of this test: 4.1.1 Temperature and humidity, and 4.1.2 Substrate movement during test. 5. Apparatus 5.1 Device, shall consist of a load-applying instrument with an accuracy of6 5 % of full scale capable of indicating peak hold. 5.2 Mounting Fixture, method to secur
10、e specimen to insure stability during test. 5.3 SMD Contact Tool, suitable to apply a uniform distribution of force to an edge of the SMD. 1 This test method is under the jurisdiction of ASTM Committee F01 on Electronics and is the direct responsibility of Subcommittee F01.18Membrane Switches. Curre
11、nt edition approved Feb. 1, 2012May 1, 2013. Published March 2012June 2013. Originally approved in 1999. Last previous edition approved in 20052012 as F199500(2005).F199512. DOI: 10.1520/F1995-12.10.1520/F1995-13. This document is not anASTM standard and is intended only to provide the user of anAST
12、M standard an indication of what changes have been made to the previous version. Because it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version of the standard as publishe
13、d by ASTM is to be considered the official document. Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States 15.4 Magnication Device, suitable to facilitate visual observation of the SMD and contact tool interface during testing (optional). 6
14、. Procedure 6.1 Pretest Setup: 6.1.1 Attach specimen to the test base to minimize movement of the substrate during test. Ensure that no damage occurs during attachment to the test base that could affect bond performance. 6.1.2 The direction of applied force shall be parallel with the plane of the ci
15、rcuit substrate. 6.1.3 The SMD contact tool shall load against an edge of the component, which most closely approximates a 90 angle with the base of the circuit substrate. Contact tool should make contact to SMD at a point equal to or less than 1 2 the total SMD height, (see Fig. 1). 6.2 In-Process
16、Test: 6.2.1 Bring contact tool into contact with SMD specimen. 6.2.2 Gradually increase force, not to exceed 225 g/s, until bond failure. 6.2.3 After initial contact with the SMD edge and during the application of force, the relative position of the contact tool shall not move such that contact is m
17、ade with the circuit plane or SMD attachment media. If the tool rides over the SMD, a new specimen shall be substituted. 6.2.4 Record force measured to shear SMD. 7. Report 7.1 Report the following information: 7.1.1 Temperature. 7.1.2 Humidity. 7.1.3 Shape and size of contact tool. 7.1.4 Orientatio
18、n of SMD to contact tool. 7.1.5 SMD information: SMD part number, plating 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 failure occured. 7.1.9 SMD size. 7.1.10 Type of encapsulant used. 8. Precision and Bias 8.1 PrecisionIt is
19、not possible to specify the precision of the procedure in Test Method F1995 for measuring Shear Force because the test is destructive allowing only limited repeatability in comparison testing. 8.2 BiasNo information can be presented on the bias of the procedure in F1995 for measuring Shear Force bec
20、ause no standard sample is available for this industry. FIG. 1SMD Contact F199513 29. Keywords 9.1 adhesion; bond strength; LED; membrane switch; shear force; SMD; surface mount ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item men
21、tioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. Thisstandardissubjecttorevisionatanytimebytheresponsibletechnicalcommitteeandmustber
22、eviewedeveryveyearsand ifnotrevised,eitherreapprovedorwithdrawn.Yourcommentsareinvitedeitherforrevisionofthisstandardorforadditionalstandards and should be addressed toASTM International Headquarters.Your comments will receive careful consideration at a meeting of the responsible technical committee
23、, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, at the address shown below. This standard is copyrighted byASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA19428-2
24、959, United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the above address 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/). F199513 3
