PCB ink is mainly divided into three lines, solder resistance, character ink three categories.

　　The line ink is used as a barrier layer to prevent corrosion of the line, and the line is protected when etched, which is generally liquid sensitive type. There are two kinds of acid corrosion resistance and alkaline corrosion resistance, alkali resistance is more expensive, this layer of ink should be dissolved with alkali after corrosion of the line.

　　Solder resistance ink is applied to the line after the line is done to protect the line. There are liquid photosensitive and heat curing, as well as ultraviolet hardening type, the pad is retained on the board, which is convenient for welding components and plays the role of insulation and oxidation prevention.

　　Character ink is used to mark the surface of the board, such as marking the component symbol, which is generally white.

　　In fact, there are other inks, such as: strippable adhesive ink, which is to protect the part that does not need to be treated when doing copper plating or surface treatment, and then can be torn off; Silver paste ink and so on.