When processing PCB boards, there may be many small and fine issues, including the electroplating layering we mentioned earlier. Today we will take a look at another common issue - tin beads. At the same time, we will also provide you with the reasons for the formation of PCB solder beads for your reference.

When PCB circuit boards leave liquid soldering, it is very easy to form solder beads. This is because when the PCB board and the solder wave are separated, they will form a tin pillar between them. However, when the tin pillar breaks and falls back into the tin cylinder, it will splash solder, which will fall onto the PCB board and form solder beads. Therefore, when designing the tin wave generator and tin cylinder, attention should be paid to reducing the height of tin descent. A small landing height helps to reduce tin slag and splashing.

The second reason for the formation of solder beads is the release of volatile substances in the PCB circuit board and solder mask layer. If there are cracks on the metal layer of the through-hole of a PCB circuit board, the volatile gases of these substances will escape from the cracks after heating, forming tin beads on the component surface of the PCB circuit board.

The third reason for the formation of tin beads is related to soldering flux. Flux will remain under the components or between the PCB circuit board and the carrier (tray used for selective soldering). If the soldering flux is not fully preheated and burned out before the PCB circuit board comes into contact with the solder wave, it will produce tin splashing and form solder beads. Therefore, the preheating parameters recommended by the flux supplier should be strictly followed.

These are the three main reasons for the production of solder beads on PCB boards, and of course, there are many other small reasons that can also cause the production of solder beads. However, with the development of technology, technical personnel have begun to have rich experience in the production of solder beads. These experiences can also quickly help technical personnel find solutions, which may be the charm of science and knowledge.