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.
