If you’re in the market for a custom silicone keypad that requires a tactile response, you may consider using metal domes. These domes are comprised of durable stainless steel and feature several coating options that can alter impact resistance. Formerly, domes used a flex circuit, PCB (printed circuit board), or membrane switch.
Types of Metal Domes
SiTech is able to install these domes utilizing a metal dome array – a double-sided adhesive that holds the metal domes and can easily peel away from a release liner, then attach all of the domes to the circuit precisely. This creates a very repeatable system that can hold dome placement within tight tolerances.
There are four main types of metal domes:
- Triangle
- Circle
- Oblong
- Four-Leg
1. Triangle Domes
Triangle domes have a good click feeling but have limitations when it comes to space. Used in applications that require large activation forces, triangle domes range up to 6,000 gf. They feature legs, which means they can be mounted to the circuit board without needing adhesive. The result? These domes can be used in high-temperature applications. They have a range of size between 5mm-13mm.
2. Circle Metal Domes
Circle metal domes are, indeed, circular, and may also be referred to as round metal domes or circle tactile domes. They’re ideal for applications requiring a low profile switch under a membrane overlay. Not only do circle domes have a longer life cycle than triangle domes, they cost about the same. A circle dome measures between 3mm to 20mm in diameter, with a range of force of 100-60 gf.
3. Oblong Metal Domes
Also known as oval or rectangle metal domes, these are used on low profile switches on circuit boards with little to no room. This is where their long and narrow shape comes in handy. The dome size varies between 3mm X 4mm up to 51 mm X 13.70mm, featuring a force range between 100 and 500 gf.
4. Four-Leg Metal Domes
Also known as the cross metal dome, four-leg metal domes are used in applications where traces of positive and negatives can be designed underneath the dome on the same side of the circuit. They have a more pronounced “clicking” feel than circle and oblong domes, but have a shorter life cycle than circle domes. They’re the tallest of all the domes and should not be used in low-profile applications. They range in size from 5mm-20mm, with a 125-500 gf range of force.
It seems there are always new kinds of metal domes becoming available every year, with features such as backlighting for circuit boards with center mounted LEDs. You can even get custom-built metal domes on request. Here at SiTech, we have experience with all types of metal domes, as well as custom dome arrays.
Contact Si-Tech
If you would like a quote on metal domes, contact us at 757-887-8488, or submit a quote online here.
