Metal Dome, which is a special component playing an important role in the electronic field, can be installed on the surface of various switches, including single-sided or double-sided printed circuit boards, flexible circuits and membrane switch panels. It is also often called metal shrapnel or metal dome, snap dome. It is mainly carefully made of extremely thin (the thickness is only within the range of 0.05mm to 0.1mm) and extremely high hardness (the general hardness is in the range of HV480 to 550).
Metal Dome occupies an indispensable position in various types of switches, and its figure can be found in many products such as membrane switches, micro switches, PCB boards, printed circuit boards, and rigid boards. It has many unique features, such as extremely stable contact performance to ensure the stability of current transmission; strong conduction performance to ensure the efficiency of signal transmission; stable and reliable rebound performance, making the switch operation have good repeatability; the hand feel is also quite excellent, which can bring a comfortable operation experience to the user.
Its working principle is clear and definite. When the metal dome is pressed, the center point of its dome will quickly sink and accurately contact the circuit on the PCB, thereby establishing a conducting loop and allowing the current to pass smoothly, thereby driving the entire product to work normally. In order to adapt to various requirements in structure and grade of different products, metal dome can carry out diversified surface treatments, such as nickel plating to enhance its corrosion resistance; silver plating to improve conductivity; gold plating to make it have better stability, etc.
In practical applications, the conductive film of metal dome is often used in products such as membrane switches, micro switches, and PCB boards, and it plays the role of a tactile switch between the operator and the product. Compared with the traditional silicone key, it has a better feel, a longer lifespan and a higher production efficiency.
There are many common shapes of metal dome. The circular one gives a sense of simplicity, the cross-shaped one has unique structural characteristics, the triangular one mainly has a relatively high stroke and relatively heavy force, and the elliptical one has a relatively low stroke and relatively light force, and the size is relatively small presenting a smooth form. In addition to these shapes, there are also square metal dome, rectangular metal dome, welded metal dome, taped metal dome and other various packages.
Not only that, metal dome can also be closely adhered to the PET with glue, which brings two benefits. On the one hand, it greatly facilitates the process of rapid assembly, and on the other hand, it realizes a very accurate positioning effect, so as to better serve the design and manufacture of various electronic products. If there is PET adhesive on the metal dome, generally it refers to adhering the metal dome to a layer of PET sheet with glue. This combined product is usually called the conductive film of metal dome or the conductive film of metal shrapnel.
• Convenient for assembly: The PET with glue can adhere several metal domes together according to a certain position, which is convenient for rapid assembly.
• Accurate positioning: Through the positioning holes on the PET, the accurate positioning of the metal dome can be achieved to ensure that it accurately corresponds to the conductive parts on the PCB or FPC and other circuit boards.
• Enhance the adhesion: The PET adhesive can make the metal dome stick more firmly on the PCB or FPC, improving the stability and reliability of the product.
When the dome switch is adhered to the PET, during the use process, especially when being pressed, a certain air cavity may be formed between the two. If there is no venting groove, these air may be compressed but cannot be discharged in time, resulting in that the pressure cannot be effectively transmitted, affecting the touch and response performance of the key, and even possible problems such as unsmooth rebound. The existence of the venting groove can allow the air to be discharged or entered in time through the channel during the pressing and rebounding process, ensuring the smoothness and sensitivity of the operation, and enabling the entire key system to work stably and reliably. At the same time, the venting groove also helps to reduce the adverse effects such as noise that may be caused by air retention.
• Good conduction performance: The dome switch itself has good conduction performance, which can ensure the stable transmission of current.
• Comfortable hand feel: The rebound performance of the dome switch can bring a comfortable touch feeling to the operator.
• Long lifespan: The lifespan of the dome switch can reach 1 million times of touch and pressure, providing reliable quality support for the product.
Discover how metal dome switches work. This guide explains their snap-action principle, tactile response, and long lifespan, making them ideal for AI products, ...
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