PCB ink is a commonly used coating in the electronic industry, which can form an insulation layer on the PCB to protect it from external environmental interference. However, the thickness of PCB ink is a very important factor. Firstly, one of the factors affecting the ink thickness of boards is the viscosity of the ink. The higher the viscosity, the poorer the fluidity of the ink, resulting in a thicker ink coating. When the viscosity of the ink is too high, it is easy to experience flow grooves and blocks, which affect the conductivity and aesthetics of the PCB. Therefore, the viscosity of ink should be adjusted reasonably according to different application scenarios. Secondly, the roughness of the PCB surface also affects the thickness of the ink. If the surface of the board is too smooth, it is difficult for ink to adhere to the surface to form a thin film, which can lead to insufficient coating thickness and affect the reliability of the circuit. If the surface is too rough, it can cause ink lakes to form, affecting the aesthetics and reliability of the board. In screen printing, the more stable the viscosity of the ink on the printing plate, the better. But after being transferred to the substrate, the viscosity increases as quickly as possible. In addition, the diluent of ink can also affect the thickness of the ink coating. Common diluents include various organic solvents and water. When the diluent concentration is too low, the ink consistency increases and the coating thickness also increases. If the concentration of the diluent is too high, it can easily cause poor ink fluidity, affecting the uniformity and thickness of the coating. In screen printing, screen printing is also an important factor affecting ink thickness. The function of the screen is to control the ink and support the template. The amount of ink penetration should be equal to the amount of ink that is transferred to the substrate by filling each mesh with ink and completely emptying each mesh as much as possible during printing. There are many operating parameters that affect the thickness of the ink, such as the hardness of the scraper, the cross-section shape, the printing speed, the printing pressure, the net distance, the scraping angle, etc. The ink scraper is made of elastic rubber. When printing, the front end of the scraper contacts the screen plate and forms an angle with it at the same time, applying pressure and moving, so that the ink in the screen frame leaks through the mesh and is transferred to the substrate. For the interface shape of the scraper, the sharper the edge of the scraper, the finer the line contact, the smaller the ink output; The rounder the edge, the more ink will be produced. Therefore, in printing, the cross-section shape of the scraper should be correctly selected. Temperature and humidity also have a certain impact on the thickness of PCB ink. The high temperature environment can promote the rapid solidification of ink and increase the thickness of coating. The wet environment may cause the ink to lose viscosity and fluidity, affecting the thickness and uniformity of the coating.
