Membrane Switches - Specifying

Electronics, Instrumentation & Electrical Database
Membrane Switch Manufacturing and Supply

Membrane Switches - Specifying Requirements

Membrane switches specifications are normally initiated by an overview engineering drawing, such as a interface control drawing (ICD), or a source control drawing (SCD). This engineering drawing will specify some or most the following:

• Over all membrane switch size requirements, height, width and thickness.
• Keypad layout and selected key symbols
• Graphic overlay colors, logos
• interface requirements
• Relevant industry manufacturing standards
• Industry testing standards
• Electrical input and output specifications
• Shielding requirements
• Environmental requirements
• Special requirements

After your vendor has reviewed your requirements, they will typically respond with their own membrane switch specification drawings. Vendor drawings will normally include recommended changes, assembly details, size recommendations, and performance expectations. After initial exchange of requirements and deliverables, meetings are conducted between the customer and vendor to compromise, and /or conclude design requirements. Several rounds of design review iterations are likely between customer and vendor. A fully functional prototype of the membrane switch should be reviewed and performance verified by customer, particularly in high production applications.

Design and engineering considerations for Membrane Switches:

• Materials use in the membrane switch graphic overlay and environment compatibility
• Adhesives used to bond the different layers together, as well, as the membrane switch to the target assembly.
• Cosmetics, embossing, enclosure colors
• Circuits, materials used, interface between circuit and target assembly
• Shielding requirements, how is this facilitated?
• Connector or interface between membrane switch and assembly
• Tactile or non-tactile, how does your switches feel or operate during actuation?
• Testing requirements, circuit and mechanical toughness of assembly requirements
• Membrane switch production testing requirements and overview

A full design review of all of the elements above should be conducted by both customer and vendor to ensure a quality product is manufactured. Other design and manufacturing considerations are likely and specific application driven.