What is Ink
Ink refers to a specialized substance used in manufacturing printed circuit boards for screen printing purposes. It is specifically formulated to meet certain physical properties and parameters to ensure high-quality printing results and proper adhesion to the board.
PCB ink needs to possess specific characteristics to achieve optimal performance. One crucial property is viscosity, which refers to the internal friction and resistance to flow of the ink. The viscosity of the ink must be suitable for screen printing and ensure proper adhesion to the board. Temperature can significantly affect viscosity, so controlling the ink temperature during the printing process is essential.
Thixotropy is another important characteristic of PCB ink. Thixotropic ink exhibits a decrease in viscosity when stirred or spread, returning to its original viscosity when left undisturbed. This property is particularly valuable in screen printing, especially when using a blade. Stirring the ink helps to liquefy it and improve its flow through the mesh, ensuring even distribution. Once the stirring stops, the ink quickly returns to its original viscosity.
Finesse, referring to the particle size and homogeneity of the ink, is also a critical aspect. In PCB ink, pigments and mineral fillers are finely ground to a particle size of not more than 4/5 microns. This fine grinding ensures that the ink flows smoothly and evenly during the printing process.
Certain precautions should be followed to ensure the best results when using PCB ink. These include maintaining the ink temperature below 20-25 ℃, as temperature changes can affect viscosity and screen printing quality. Thoroughly stirring the ink before use, allowing it to stand if exposed to air, and checking viscosity if dilution is required are also important steps. Additionally, promptly sealing the ink after use to prevent contamination, using compatible cleaners for screen cleaning, and maintaining a good exhaust system for drying the ink are crucial for maintaining ink quality.