PCB contact/pads processing
Anti-soldering green paint covers most copper surface of the circuit, exposing only the terminal contacts for parts welding, electrical testing and circuit board insertion.This endpoint needs to be protected by an appropriate protective layer to avoid oxides generated at the endpoints connected to the anode(+) during long-term use, which may affect circuit stability and cause security concerns.
Electroplated hard gold: a layer of nickel layer and a high chemical passivity gold layer is plated on the connector endpoint of the circuit board (commonly known as golden finger) to protect the endpoint and provide good connection performance, which contains an appropriate amount of cobalt and has excellent wear resistance characteristics.
Tin spraying: a layer of tin lead alloy layer is covered on the welding end of the circuit board by hot air leveling to protect the end of circuit board and provide good welding performance.
Pre-welding: a layer of anti-oxidation pre-welding film is covered on the welding end of the circuit board in a way of impregnation to temporarily protect the welding end and provide a relatively flat welding surface before welding, so as to achieve good welding performance.
Carbon ink: a layer of carbon ink is printed on the contact end of the circuit board by screen printing to protect the end point and provide good connection performance.
The circuit board is cut into the required size by CNC molding machine (or punching machine).During cutting, the circuit board is fixed on the bed (or die) by the pin through the positioning hole drilled previously.After cutting, the gold finger part is then bevelled to facilitate the use of circuit board insertion. For the PCB of polychip forming, X shape fracture line (known as v-cut in the industry) should be added to facilitate customers to split and disassemble after plug-in. Finally, the chip on the circuit board and the surface of the ion pollutants washed.