The membrane switch is composed of multiple layers of films. Different materials in these film layers play different roles and together perform the functions of the membrane switch in electrical products. Among them, the circuit layer is the main functional layer of the membrane switch. It is an electronic circuit designed according to the required functions of the circuit product, with conductive silver paste printed on PVC, PC or PET materials, and then combined with the panel layer and isolation layer to form the membrane switch. When manufacturing the circuit layer of the membrane switch, attention should be paid to the prevention and handling of silver migration.

　　Multilayer film switchConductive silver pastePrevention and handling of Bank of China's migration:

　　Try to widen the gaps other than the silver circuit (wires) as much as possible, while maintaining a low voltage (electric potential). 
2. On the silver circuit, a layer of carbon paste or blue transparent insulating ink with a thickness greater than 30 μm can be applied. 
3. To prevent the silver from accelerating its migration in a humid environment, air vents should be added around the membrane switch during the design process. 
4. Pay attention to the hygiene conditions of the printing environment. When applying the insulating coating by screen printing, avoid dust and pinholes. If dust or debris enters the space between the conductive wires and circuits, under certain conditions, it may cause a decline in electrical performance. 
5. If the insulating coating of the silver paste circuit on the screen-printed circuit board is insufficiently cured or has excessive solvents, it will reduce the insulation performance of the insulating layer, thereby lowering the anti-migration performance of the silver in the humid air medium. 
The drying process after screen printing of conductive silver paste should adopt the following three-stage curing method: 
a. 2/3 of the time (at the specified temperature); b. Place at room temperature for 1 to 2 hours; c. Use 1/3 of the time (at the specified temperature) for infrared drying. 
This will enable the resistance to reach its optimal value. 
Use protective insulating coating and transparent green ink. The UV light curing should be thorough, with a wavelength of 180 to 420 nm and a power of 80 to 120 W/cm. The speed of UV exposure should be accurately adjusted. The screen used is 160 to 300 mesh per inch (64 to 120 T/cm, depending on the situation). 
The content of this article has been carefully edited by Saiya Paints. We hope it will be helpful to everyone. For more information about silver paint and conductive silver paint, please leave a message or call for consultation.