Depth analysis of the difference between PCB spray tin and PCB tin

The cost of a PCB tinplate is relatively low because it only sprays tin on the PCB above the pad, while tin plating includes wires as well as tin.

As the name implies, PCB tin is chemically applied to the position of the PCB pad, sinking a layer of tin, the thickness is very thin, generally 10~30 microns, the main purpose is to prevent oxidation, better for SMT tin fusion, in fact Kim, OSP, the same purpose. Need to be on tin in SMT.

PCB tinning is a physical method of spraying a layer of tin, the thickness is generally 50 ~ 150 microns, relatively thick. Don't put on tin when you are in smt, you can apply tinned solder.

The composition of the two tins must be different. The tin of the PCB is tin salt, which is made of an acidic solution containing tin. However, PCB tin is generally used as an alloy of tin, which is generally divided into lead and lead-free (never use pure tin, the melting point is high).

Chemical tin, also known as immersion tin, is a surface treatment form for the surface protection of the pad. Like OSP, immersion gold, and immersion silver, it mainly protects the surface copper foil (PAD).

Tin plating is a process in which the PCB factory protects the lines and holes of copper before etching. When the etching is performed, the protective tin is removed and then transferred to the next production process for solder masking. print! Therefore, the tin plating process is not seen in the SMT patch factory.