In the SMT welding technology, many customers usually have requirements for the brightness of the solder joints. After all, the brightness of the solder joints will give us a bright feeling. In the process of SMT chip processing, it is not guaranteed that the brightness of each solder point can reach the level of sparkling. So what is the reason for the insufficient gloss of solder joints in SMT chip processing?
1. The tin powder in the solder paste has oxidation appearance.
2. The flux itself in the solder paste has additives that form a matting effect.
3. The preheating temperature of reflow soldering is low in SMD processing, and there are residues that are not easy to evaporate on the surface of the solder joints.
4. After soldering, there are rosin or resin residues on the appearance of the solder joints. This is a phenomenon that is often seen in actual operations, especially when rosin-type solder paste is used. The spot is slightly brighter, but the presence of its residue often affects this effect, especially in larger solder joints or IC pins; if it can be cleaned after soldering, the solder joint gloss should be improved.
5. Since there is no standard for the brightness of solder joints, if the products after soldering without silver solder paste are compared with those after soldering with silver solder paste, there will definitely be some distance, which requires customers to choose solder paste. should clarify their solder joint requirements to the supplier.