Characteristics and classification of PCB inks

PCB ink refers to the ink used in PCB. Now let’s share with you the characteristics and types of PCB ink?

1、 Characteristics of PCB ink

1-1. Viscosity and thixotropy
In the manufacturing process of printed circuit boards, screen printing is one of the indispensable and important processes. In order to obtain the fidelity of image reproduction, the ink must have good viscosity and suitable thixotropy.
1-2. Fineness
The pigments and mineral fillers of PCB inks are generally solid. After fine grinding, their particle size does not exceed 4/5 microns, and form a homogenized flow state in solid form.

2、 Types of PCB inks

PCB inks are mainly divided into three categories: circuit, solder mask and silkscreen inks.

2-1. The circuit ink is used as a barrier to prevent the corrosion of the circuit. It protects the line during etching. It is generally liquid photosensitive; There are two types: acid corrosion resistance and alkali corrosion resistance.
2- 2. Solder resist ink is painted on the circuit after the circuit is finished as a protective line. There are liquid photosensitive, heat curing and UV hardening types. The bonding pad is reserved on the board to facilitate the welding of components and play the role of insulation and oxidation prevention.
2-3. Silkscreen ink is used to mark the surface of the board, such as the symbol of components, which is usually white.

In addition, there are other inks, such as strippable adhesive ink, silver paste ink, etc.