The metal dome is the only metal component in the membrane switch and is widely used. Under the current circumstances, many products use metal domes in a confusing manner, especially in flexible circuits. They are only used as a component to provide tactile feedback, which causes many drawbacks to the performance of the membrane switch and even causes the membrane switch to lose its due effect.
Best Technology introduces the characteristics, specifications, functions, selections and common problems of metal domes one by one for your reference, so as to better utilize the role of metal domes and improve the reliability of membrane switches.
1. Characteristics of metal dome
Metal domes are usually made of 301 or 304 stainless steel. For mylar, we have the thickness of 0.05mm and 0.075mm (both are with adhesive). And the mylar with the thickness of 0.05mm is the most commonly used. In addition, we can also produce some metal domes with special thickness according to customer requirements. The main parameters of metal domes are as follows:
Lifespan: 4 to 5 million times
Contact Bounce (on) : <.3ms
Contact Bounce (off) : <6ms
Voltage/Current Maximum: 12 ma @ 24 volts DC, RL
Contact Resistance:<100 ohms
2. The function of shrapnel
- Use the conductivity of metal to connect the two-pole contacts of the switch.
- End the rebound of the metal dome and provide tactile feedback to the operator
3. Common types and specifications of metal domes
First of all, according to the shape, there are round, triangular, oval and four-legged metal domes. In order to make the bottom edge of the metal dome contact smoothly and increase the stroke, as well as overcome the frictional resistance of the bottom edge to the substrate when the dome moves and facilitate scheduling, corresponding support dots are punched on the edges of metal domes of different shapes. . At the same time, the domes are classified according to their external dimensions, operating strength, stroke height, etc. So there are many types of metal domes. Best Technology customizes different metal dome shapes and specifications according to different product application requirements.
4. Application of metal domes
Metal domes are mainly used in PCBs and membrane switches containing circuit boards. In membrane switches, the three major characteristics of metal domes are conduction, rebound, and touch. It can be mainly used in consumer products such as electronic keyboards, remote control switches, POS machines, etc., as well as mechanical products such as factory machine consoles and some key switches.