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.
They are primarily used in membrane switches, dome-contact switches, PCBs, FPCs, medical devices, and other products. How button springs work: The button spring on a membrane switch is positioned over a conductive area on the PCB (mostly above the gold fingers on the circuit board). When pressed, the center of the spring depresses and makes contact with the circuit on the PCB, thereby forming a circuit. Current flows, allowing the entire product to function normally.
Customizable Parameters
Shape: Circular, Cross-shaped, Triangular, Oval, Rectangular, Square, Custom Shapes
Dimensions (Diameter): Typically 3 mm to 25 mm
Actuation Force: Standard range 100 gf to 600 gf (light/standard/firm), with some options as low as 60 gf or as high as 6,000 gf
Material: SUS301 (high-elasticity stainless steel, most commonly used), SUS304, phosphor bronze
Surface Treatment (Plating): Nickel plating (rust-proof), silver plating (excellent conductivity), gold plating (high corrosion resistance and stability)
Contact Type: Standard smooth surface, silver-plated contacts, gold-plated contacts
Substrate and Structure: PET film (Mylar) substrate; single-layer, double-layer (with spacers), EMI printing (anti-static), with plungers, and other structures
Array and Mounting: Single individual components, or custom multi-component assemblies per drawings (including positioning holes and alignment marks)
Hongmao’s metal springs are categorized by shape into: round 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. Both single-sided and double-sided plating options are available.
Parameters such as the spring force/return force, click sound, travel, and height of the switch plates can be adjusted according to customer requirements. Regardless of the size or force value you need, we will do our utmost to manufacture them for you.
Information Typically Required for Custom Orders
To ensure an accurate evaluation and expedite prototyping, we recommend preparing the following information in advance:
PCB/FPC layout drawings (PDF or GERBER format) and button location dimensions.
Specific performance requirements: form factor, dimensions, actuation force, contact type, operating stroke, and expected service life.
SMT assembly requirements: Single components or array mounting? Are registration holes or outer frame dimensions required?
Application scenarios and environments: Product type (home appliances/medical/industrial control/automotive/consumer electronics), as well as any special requirements for temperature resistance, moisture resistance, or chemical corrosion resistance.
