The generation of solder bar reduce tin slag has its inevitability and regularity, and the procedures of paying attention to various aspects during the production process can be reduced. So, how can solder bar reduce tin slag?

From the point of view of the operation process, the higher the wave peak is, the larger the solder surface is in contact with the air, the oxidation will become more serious, and the more tin slag will be. Therefore, the wave peak should not be too high, generally speaking, it should not exceed 1/3 of the thickness direction of the PCB, which is equivalent to saying that the top of the wave peak should exceed the soldering surface of the PCB circuit board, but should not exceed the electronic component surface.

If the wave crest is very unstable, when the liquid solder falls back from the peak, it may carry the air inside the molten solder, and the oxidation of tin is rapid. In the wave soldering process, the copper on the surface of the pcb circuit board and the copper on the pins of electronic components They are constantly melting into the molten solder. Copper and tin will form Cu6Sn5 intermetallic compound with each other. The melting point of this compound is above 500 ° C, so it exists in solid form. In addition, the current density of this compound is 8.28g/cm3, while the density of Sn63Pb37 solder bar is 8.80g/cm3, so generally speaking, this kind of compound will float on the surface of liquid solder in the form of bean curd residue.

Therefore, the removal of copper is very important. The operation process is as follows: stop the wave crest, and the heating device of the tin furnace is in daily operation. On the one hand, it can clean up various residues on the surface of the tin furnace, revealing the mercury-like mirror pattern. Then lower the working temperature of the tin furnace to 190-200°C (the solder is still in a liquid state at this time), and then use iron spoons and other equipment to stir the solder for 1-2 minutes to help the tin-copper compounds inside the solder float up and then place it for 3-5 hours or so. Due to the low density of tin-copper compounds, the tin-copper compounds will gradually float on the solder surface after being placed. At this time, the tin-copper compounds on the surface can be cleaned with iron spoons and other equipment.