ASTM F3290-17

5.1 Membrane switches or printed electronic devices are tested for function and aesthetically inspected by the manufacturer before release to the end user. The user can unknowingly damage the device beyond repair prior to, or during, the application (laminating) process.

5.2 Awareness and proper techniques are essential to the end user and this guide should be noted on all drawings, quality control documentation, and assembly instructions. Proper training and practice must be provided to work area supervisors and their staff.

5.3 Concerning materials choice, consistency, and design in use, it is important to know what to look for and how to design for durability and to test for or prevent potential failures, or both.

5.4 Component failure due to handling damage is one of the most common causes of customer complaints. It is the end user’s responsibility to ensure that the product is not damaged during installation

5.5 In the event of component failures a comparison of pre- and post-assembly test performance may help determine the cause of failure. Even if an acceptable change is noted, it may be the result of the unit being over stressed and the application process should be reviewed and changed if necessary. It is important to determine if the change or failure is one that should have withstood the application process, or whether the application process is causing undue stress. Bend, Crease, and Mandrel Testing in accordance with Test Methods F2749, F2750, and F3147 may be necessary to determine the root cause and location of failure.

1.1 This guide covers proper handling and application of a flexible circuit membrane switch, or printed electronic assembly to its final support structure to avoid mechanical or electrical failure.

1.2 Damage of internal tactile devices or surface mount device (SMD) components can occur with excessive flexing or bending during lamination, repositioning, from uneven support surface, air entrapment, or pressing keys when unsupported.

1.3 Design considerations and material selection can impact the membrane switch or the printed electronic device’s ability to endure the mechanical stress that can occur in handling, application and use. These should be considered as early as possible in the design phase.

1.4 Recent advancements in printed electronic polymer materials have shown increased reliability from flexing and creasing, replacing copper flex circuits in many cases.

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.