Precautions for welding FPC flexible circuit board:
1) Because polyimide is hygroscopic, the circuit must be baked before welding (lasting for 1h at 250 ° F).
2) When pads are placed on large conductive areas, such as ground plane, power layer or heat sink, the heat dissipation area should be reduced. This limits heat dissipation and makes welding easier.
3) When manually welding pins in dense places, try not to continuously weld adjacent pins, and move the welding back and forth to avoid local overheating.
4) Shorten the connection between high-frequency components and reduce EMI interference. Components with large weight (such as more than 20g) shall be fixed with supports and then welded.
5) The arrangement of elements shall be as parallel as possible, which is not only beautiful but also easy to weld, and it is suitable for mass production. When FPC circuit board is heated for a long time, copper foil is easy to expand and fall off. Therefore, large area copper foil should be avoided.