Triangular Metal Domes are specifically designed for installation on single-sided or double-sided printed circuit boards, flexible circuits, and films with through-holes. For applications requiring a good tactile feel but with limited space—such as small handheld devices—our triangular series of metal tact switches is the ideal choice. For the same diameter, triangular tact switches provide the greatest actuation force. With an actuation force of up to 6,000 gf (6 kg), these triangular tactile springs can function as gravity-controlled switches, preventing accidental operation.
Metal springs are available in sizes ranging from 5 mm to 13 mm, with actuation forces ranging from 150 to 6,000 gf. Parameters such as actuation force, rebound force/return force, click rate, travel, and height can be adjusted according to customer requirements.
Button springs (also commonly known as “pot springs,” “metal domes,” or “snap domes”) are made from ultra-thin (0.05 mm–0.1 mm thick) or ultra-thick (typically with higher hardness) 301 or 304 stainless steel. Button springs are a critical component of switches.
Button springs are primarily used in membrane switches, dome-contact switches, PCBs, FPCs, medical devices, and other products. How button domes work: The button dome on a membrane switch is positioned over the conductive area on the PCB (mostly above the gold fingers on the circuit board). When pressed, the center of the dome depresses and makes contact with the circuit on the PCB, thereby forming a circuit. Current flows, allowing the entire product to function normally.
Hongmao’s metal dones are categorized by shape into: circular metal springs, cross-shaped metal springs, triangular metal springs, and oval metal springs. Diameters range from 3 mm to 20 mm, and actuation forces range from 100 g to 600 gf. Based on surface plating treatments, they can also be classified as: gold-plated, nickel-plated, silver-plated, and mirror-finished. There are two types: single-sided plating and double-sided plating.
Key Features
Triangular Metal Dome was originally designed to achieve higher actuation force within a limited space.
Significant Force Advantage: For the same diameter, the triangular structure typically provides higher force than circular or cross-shaped designs. While conventional force ranges typically fall between 100 gf and 600 gf, triangular springs can easily exceed 600 gf and even cover a wide range from 150 gf to 6,000 gf—this is their most outstanding capability.
Optimized Conductivity Design: The structure typically features a single contact point in the center and one contact point on each of the three sides. This design ensures more thorough and stable contact with the gold fingers on the PCB, thereby enhancing electrical reliability.
Clear Application Limits: Its advantages come with trade-offs. Due to its structure, its service life is relatively shorter than that of round and cross-shaped leaf springs (some sources indicate over 300,000 cycles), but for many consumer electronics products, this is usually sufficient to cover the product’s entire lifecycle. Therefore, it is primarily used in products with relatively sparse button layouts and less demanding assembly requirements, such as toys and desk phones.
