Membrane Switches with Copper FPC Circuitry
Most membrane switches are manufactured with screen-printed silver circuits, but for more complex designs a copper FPC circuit layer might be required. Copper flex circuits can be manufactured reliably with many small surface mount components and double sided circuitry. To contrast, screen-printed silver circuits can only reliably accommodate a few surface mount components with large footprints (typically 0.060″ x 0.030″ or bigger). This is because the conductive silver epoxy used with silver circuits is more prone to short circuits than solder paste, and conductive silver epoxy does not allow rework.
Advantages of copper circuits
- Copper flex circuits can reliably accommodate complex double sided circuit designs.
- Copper flex circuits can have many small surface mount components mounted on them without reliability issues or fallout during manufacturing. Components such as RGB LEDs will require copper circuitry and cannot typically be mounted on silver circuits.
- Copper flex circuits can have fine pitch ZIF tails such as 1mm, 0.5mm, and 0.35mm pitch. They can also be fitted with 2.54mm female housings.
- Copper Flex ZIF tails can be inserted multiple times without damaging the ENIG Gold plating on the contacts.
Advantages of silver circuits
- Screen-printed circuits are most reliable as single sided circuits. Crossover circuitry or through-hole connections can decrease reliability, and cause fallout during manufacturing.
- Silver circuits can have some surface mount LEDs bonded to them with conductive silver epoxy, but the components must be 0.060″ x 0.030″ or larger. Typically designs with 8 or more LEDs are better suited for copper flex circuits than silver.
- Carbon contacts on silver circuits wear out quickly when repeatedly inserted into ZIF connectors.
- Circuit termination methods are limited to 1mm pitch ZIF or 2.54mm pitch female connectors.
How do I order membrane switches with copper circuitry?
At Sterling Electrode LLC we are America’s best membrane switch designers. We have extensive experience designing membrane switches with copper flex circuits. If you have a design already then we can always quote within 24 hours. If you need us to create a design for you, then we just need some basic information about your requirements including the size, shape, number of surface-mount components, circuit termination, and graphic artwork. Fill out our contact form today or send us an email at “Sales@membraneswitch.com”.
