In order to improve the fidelity of image reproduction, the ink must have good viscosity and appropriate thixotropy. The so-called viscosity is the internal friction of the liquid, that is, the friction force generated by the internal liquid when one layer of liquid slides on another layer of liquid under the action of external force. Sliding inside a thick liquid encounters greater mechanical resistance, while a thinner liquid has less resistance. The unit of viscosity is poise. In particular, it should be pointed out that temperature has a significant effect on viscosity.
What are the types of PCB ink
Thixotropy is a physical property of a liquid, that is, the viscosity of the liquid decreases under stirring, and quickly returns to its original viscosity after standing still. With stirring, the thixotropic effect lasts long enough to rebuild its internal structure. In order to obtain high-quality screen printing results, the thixotropy of the ink is very important. Especially during the scraping process, the ink is stirred into a liquid. This function can speed up the speed of ink passing through the mesh, and promote the uniform connection of ink separated from the original mesh line into a mesh. Once the squeegee stops and the ink returns to static, its viscosity will quickly return to the original desired data.
Pigments and mineral fillers are usually solids. After fine grinding, its particle size does not exceed 4/5 micron, and it forms a uniform flow state in solid form. Therefore, it is very important to require the ink to have fineness.
PCB inks are mainly divided into three categories: circuit inks, solder resist inks and character inks.
Line ink acts as a barrier to prevent corrosion of lines. It protects the lines during etching. It is usually liquid photosensitive. Acid corrosion resistance and alkali corrosion resistance. Alkali resistant is more expensive. This layer of ink should be dissolved with alkali after corrosion.
What are the types of PCB ink
After the circuit is completed, apply solder resist ink on the circuit as a protection for the circuit. Available in liquid photosensitive, heat cured and UV hardened. Pads are reserved on the board, which is convenient for component welding and plays the role of insulation and anti-oxidation.
Hengfu ink is used to mark the surface of the circuit board. For example, it is usually white.
In fact, there are other inks, such as peelable adhesive inks, which protect parts that do not need to be treated during copper plating or surface treatment, which can then be removed; silver paste inks, etc.
The above are the types of ink on the PCB circuit board, I hope to provide you with some help!
