Wave soldering - Solution for point pulling

The tip of the wave crest solder joint is that the solder on the wave crest solder joint is in the shape of milky stone or water column when the circuit board is welded by the wave crest, and this form is said to be the tip. Its essence is that the solder is generated by gravity greater than the internal stress of the solder, and the reasons for this are analyzed as follows:

1. Poor flux or too little: this reason will cause the soldering solder to be wet on the surface of the solder spot, and the solder on the surface of the copper foil is very poor, at this time, it will produce a large area of the PCB board.
2. The transmission Angle is too low: the PCB transmission Angle is too low, the soldering solder is easy to accumulate on the surface of the solder joint in the case of relatively poor fluidity, and the condensation process of the solder is eventually due to the gravity is greater than the internal stress of the solder, forming a pull tip.
3. Solder crest velocity: the scouring force of the solder crest on the solder joint is too low, and the fluidity of the solder is in a poor state, especially lead-free tin, the solder joint will adsorb a large number of solder joints, which is easy to cause too much solder and produce a pull tip.
4. PCB transmission speed is not suitable: the setting of wave soldering transmission speed must meet the requirements of the welding process, if the speed is suitable for the welding process, the formation of the tip can be unrelated to this.
5. Too deep tin immersion: too deep tin immersion will cause the soldering solder joint to be completely coked before leaving, because the surface temperature of the PCB board is too high, the PCB solder will accumulate a large amount of solder on the solder joint due to the diffusability change, forming a pull tip. The solder depth should be appropriately reduced or the welding Angle increased.
6. Wave welding preheating temperature or tin temperature deviation is too large: too low temperature will make the PCB into the solder, the solder surface temperature drops too much, resulting in poor fluidity, a large number of solder will accumulate on the solder surface to produce a pull tip, and too high temperature will make the flux coking, so that the wettability and diffusion of the solder become worse, may form a pull tip.