SMT touch switch is an electronic switch, which belongs to the category of electronic components. It first appeared in Japan [called: sensitive switch] when it was used to meet the conditions of operating force, pressure the switch operation direction, the switch function was closed and connected, when the pressure was removed, the switch was disconnected, and its internal structure was realized by the change of metal spring force. The chip touch switch is composed of an insert, a base, a spring piece, a button and a cover plate. A polyimide film is added on the spring piece of the waterproof light touch switch.
Scope of application
1. Audio and video products: MP3, MP4, DVD;
2. Digital products: digital camera, digital camera, etc;
3. Remote control: remote control for vehicle, roll door and home anti-theft products;
4. Communication products: mobile phone, car phone, telephone, building equipment, PDA, etc;
5. Household appliances: TV, microwave oven, rice cooker, electric wind, electronic body scale, electronic fat scale, electronic kitchen scale, etc;
6. Security products: Video walkie talkie, monitor, etc.; 7. Toys: electronic toys, etc;
8. Computer products: camera, recorder, etc;
9. Fitness equipment: running machine, massage chair, etc;
10. Medical equipment: sphygmomanometer, thermometer, hospital call system, etc.
11. Others: banknote inspection pen, laser pen, etc;
Selection method
The key factors that affect the quality of SMT touch switch are the protection, solderability, conduction reliability, life, handle, production process and installation size!
First of all, it is the base material of the pin. The base material of the pin of the light touch switch is brass or phosphor copper (the low grade is iron). In order to reduce the contact resistance, the pin is basically plated with silver. The silver will be oxidized when meeting the SO2 gas in the air, which will directly affect the solderability and contact resistance of the switch (waterproof switch). Therefore, the high-quality light touch switch must first have the silver plating thickness and silver plating process on the base material of the pin The order of silver plating on the market is as follows: silver plating thickness: above 0.3um (after silver), 0.2um (thin silver), 0.1um (white) silver plating process: nickel plating and silver plating on the substrate, copper plating and silver plating on the substrate, and direct silver plating on the substrate. Whether the substrate has protective agent treatment after silver plating or whether the switch has dust-proof and waterproof function is very important, otherwise, even the best plating process can be achieved When silver is treated, the switch will also be oxidized.
Secondly, the key influencing factor of conduction reliability is the structure of the contact point. Because the function of the light touch switch is to conduct contact between the contact point and the spring piece, the larger the contact surface of the contact point is, the better. The contact surface is determined by the structure. There are probably three types of structures in the market, and the order of advantages and disadvantages is as follows:
The service life and handle of big bubble (crater type) "O-type contact", "slotted type" 2-point contact "and flat bubble type" 1-point contact "are determined by the stroke and spring piece of the light touch switch. The shorter the stroke is, the lighter the sound is, the longer the life is; otherwise, in the case of fixed shrapnel technology, the service life of the light touch switch is mainly determined by the stroke or sound;
In addition, the key factor to determine the life of shrapnel is stamping technology. The stamping technology in Japan and Taiwan is very popular in China. Therefore, in the case of technology improvement, whether the requirements for imported materials are reduced. For example, there are four main types of 160gf shrapnel life in the market
For the production process of about 50000 times (domestic phosphorous copper or relatively backward stamping technology), 100000 times or more (stainless steel) production process, with accessories, the final impact on the quality is the assembly process. The assembly process depends on the management ability of the production company, the quality meaning of employees and the quality assurance ability. The final product quality with different assurance capabilities is certainly different The market assembly methods include labor and machine. The machine assembly cost is low, but the product quality is low. The manual assembly cost is high, but the quality is also high. The methods and items of factory inspection also affect the quality of the final touch switch, such as whether the appearance, feel, conduction, resistance and other items are spot checked or fully inspected. For example, the scrap rate required by some large factories is measured by ppm or zero defect, so it is necessary to set up sampling inspection or quality inspection after setting up full inspection in factory inspection.
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