Icicle refers to the protrusion of the solder tip on the solder joint of the copper foil circuit terminal of the PCB , and there is an obvious tip, which is called solder flag.

What are the factors that cause solder flag?

1. During manual soldering, the soldering iron tip on the operator's hand may be removed prematurely when the solder is not completely melted and fixed.

2. The temperature is too low during soldering. But most of the reasons are that the flame iron head is removed too late, the welding time is too long, and the flux is vaporized, that is to say, the drawing tip is related to temperature and operation.

What are the effects of solder flag on PCB?

In addition to the poor appearance of the icicle of the PCB, when the solder joints are drawn beyond the allowable length, the insulation distance between the solder joints is reduced, which is easy to cause bridging. In high-frequency and high-voltage circuits, it will cause sparks, so pay special attention.

Solution: The welding time should not be too long. Once the phenomenon of sharpening occurs, it is only necessary to add flux and re-solder. In automatic soldering, attention should be paid to the angle of the printed circuit board away from the solder level.