Flexible circuit board FPC hot air leveling

Hot air leveling was originally developed to apply lead tin to rigid printed circuit boards. Due to its simplicity, it has also been applied to flexible printed board FPC. Hot air leveling is to immerse the board directly into the molten lead slot, and excess solder is blown away by hot air. This situation is very demanding for flexible printed circuit board FPC. If the flexible printed circuit board FPC cannot be immersed in the solder without any measure, the flexible printed circuit board FPC must be sandwiched between the screens made of titanium steel. Then, it is immersed in molten solder. Of course, the surface of the flexible printed board FPC is also cleaned and coated with flux.

Due to the harsh hot air leveling process conditions, the solder is easily drilled from the end of the cover layer to the underside of the cover layer, especially when the bond strength of the cover layer and the copper foil surface is low, which is more likely to occur frequently. Since the polyimide film is apt to absorb moisture, when the hot air leveling process is used, the moisture absorbing moisture causes foaming or even flaking of the cover layer due to rapid thermal evaporation, so drying and moisture prevention are required. FPC hot air leveling. management.