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4.1 Resistance is useful to manufacturers and users when designing membrane switch interface circuitry.1.1 This test method covers the determination of the circuit resistance of a membrane switch.1.2 This standard does not purport to address all of the safety concerns, if any, associated with 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.

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4.1 Current carrying capacity is used by designers and manufacturers of electronic interface circuitry to ensure that the membrane switch can reliably handle the loads occurring in normal use and under extreme circumstances. A thorough understanding of CCC allows manufacturers to take it into account when developing design rules for membrane switches.4.2 Failures due to exceeding the CCC of a circuit may take the form of a significant change in conductor resistance, insulation breakdown (shorts), or conductor breakdown (opens).4.3 Since a number of design parameters, such as trace width, ink film thickness, and heat transfer (mounting substrates, active cooling such as fans) affect the final test results, any conclusions should only be applied to specific designs, rather than to a general combination of materials.4.4 Current carrying capacity tests may be destructive and units that have been tested should be considered unreliable for future use.4.5 Current carrying capacity may be significantly different for static loads and dynamic (that is, cycling) loads. Failure modes are also generally different.4.6 The use of a thermocouple to monitor the temperature of the UUT may be helpful to monitor the progress of the test.4.7 Initial expected starting current should be calculated in advance to prevent damage to test equipment.1.1 This test method covers the determination of the current carrying capacity of a conductor as part of a membrane switch.1.2 This test method may be used to test a circuit to destruction, that is, to determine its maximum current carrying capacity, or it may be used to test the ability of a circuit to withstand a desired current level.1.3 This test method applies only to static conditions, and does not apply to contact closure cycling of a membrane switch under current load (test method forthcoming).1.4 This standard does not purport to address all of the safety concerns, if any, associated with 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.

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4.1 The existing Test Method F1995, while very useful, is difficult to conduct if an encapsulating dome is applied, and does not reveal the possible failures caused by mechanical stress incompatibility in the overall SMT joint. This mandrel bend test will reveal possible mechanical stress incompatibility between the various adhesives which can result in latent field failures during production handling or with thermal cycling in normal use.4.2 The existing Test Method F2750 does not include specifics for SMD attachments and only addresses the conductivity change of the conductive trace.4.3 The different combinations of SMD types, attachment medias, circuit substrates and process variation can account for significant variation in test outcome.4.4 Bending of printed flexible circuit or their components can affect their visual appearance, mechanical integrity or electrical functionality. This test method simulates conditions that may be seen during manufacture, installation, or use.4.5 Bend testing may be destructive, therefore any samples tested should be considered unfit for future use.1.1 This test method covers a means to test a completed Surface Mounted Device (SMD) joint for bond strength and inter-layer stress compatibility1.2 A completed SMD joint includes; SMD (LED, resistor, etc), PTF ink land (typically silver), conductive adhesive (typically silver), staking compound (non-conductive), and encapsulant (non-conductive).

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5.1 Permittivity and dissipation factor are fundamental design parameters for design of microwave circuitry. Permittivity plays a principal role in determining the wavelength and the impedance of transmission lines. Dissipation factor (along with copper losses) influence attenuation and power losses.5.2 This test method is suitable for polymeric materials having permittivity in the order of two to eleven. Such materials are popular in applications of stripline and microstrip configurations used in the 1 GHz to 18 GHz range.5.3 This test method is suitable for design, development, acceptance specifications, and manufacturing quality control.NOTE 2: See Appendix X1 for additional information regarding significance of this test method and the application of the results.1.1 This test method permits the rapid measurement of apparent relative permittivity and loss tangent (dissipation factor) of metal-clad polymer-based circuit substrates in the X-band (8 GHz to 12.4 GHz).1.2 This test method is suitable for testing PTFE (polytetrafluorethylene) impregnated glass cloth or random-oriented fiber mats, glass fiber-reinforced polystyrene, polyphenyleneoxide, irradiated polyethylene, and similar materials having a nominal specimen thickness of 1/16 in. (1.6 mm). The materials listed in the preceding sentence have been used in commercial applications at nominal frequency of 9.6 GHz.NOTE 1: See Appendix X1 for additional information about range of permittivity, thickness other than 1/16 in. (1.6 mm), and tests at frequencies other than 9.6 GHz.1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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3.1 Destructive and non-destructive tests characteristics must be evaluated to ensure the membrane switch will operate and survive the application it was designed for. It is not feasible for all tests to be performed on each membrane of a production lot. However, there are some non-destructive tests that must be performed on each switch assembly to ensure 100 % functionality and checking each i/o point for unwanted electrical continuity to any other i/o point is one of these characteristics.1.1 This standard establishes a test method for detecting unwanted electrical shorts in a membrane switch.1.2 Since this is a non-destructive test, it can be performed on a membrane switch that is going to be mounted and used in its intended environment.1.3 This standard does not purport to address all of the safety concerns, if any, associated with 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.

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