The reason for using rosin when soldering iron
1. The tip of the soldering iron does not stick to tin. After dipping in rosin, it is easy to melt the tin and stick to the soldering iron.
2. The tin wire is made very thin because it is easy to melt and stained with rosin, so that the thin tin wire can be melted into a round and full drop shape instead of running around.
3. The solder is directly dripped on the solder joints. If the solder joints are cleaned or oxidized, it is easy to be loose and fall off when touched. Adding rosin is beneficial to remove the negative effect of oxidation, making the solder stronger.
4. Without solder, it is easy to stick the solder when the soldering iron is removed from the solder joint, resulting in unsightly solder joints.
5. Drop it directly, indicating that the process requirements are not high during welding, or there is too much dripping, resulting in unnecessary waste.
Rosin is a strong reducing agent that can reduce aluminum oxide and tin-lead oxides (both lead and tin have two oxides corresponding to two valence states) to generate corresponding metals and welding slag, which should not be stained normally. solder.
The tip of the soldering iron does not occupy tin, but the melting point of 60 tin-40 lead solder is relatively high. No matter the metal oxide or the organic oxide formed by the oxidation of rosin has poor thermal conductivity. Down.
I don't know what to solder, it is a good way to deliberately oxidize the back of the soldering iron tip, so that the front will continue to eat tin and finally drip. The tin wire is very thin. The thinnest tin wire is of poor quality and has extremely poor fluidity.
Finally, after the solder balls drip onto the metal surface, there is no time for solid-liquid fusion, the contact surface is loose and unstable, and it is very easy to solder.
