Screen printing is a process of transferring ink to the substrate for printing by moving the screen and the squeegee under a certain squeegee pressure. The screen and the squeegee are both insulators. In the screen printing, they are relatively scraped and rubbed against each other, especially when the humidity is low, it will cause static electricity affecting the surface charge distribution of the substrate.
From an atomic point of view, electrostatic phenomenon is that the positively charged nucleus in each atom neutralizes with the surrounding negatively charged electron cloud. When the material is separated by friction and contact, the electrons in the insulating material will be released to the surface of the material.
Static electricity is reflected in the screen printing workshop. The screen printing workshop often causes the screen template to bounce off the substrate. The ink in the pattern part of the screen will also be removed from the substrate due to the fluffy "spider silk" formed by the screen. When the screen continues to rise, this kind of "clam silk" drifts with the wind before and after it is scattered on the substrate, making the surface of the substrate smudged, with fuzzy patterns and rough edges.
For the screen printing workshop, the humidity of the environment should be controlled between 50-65%RH during the gluing operation. The drying time in this humidity range is more suitable, and if the humidity is above 70%RH, the drying time will be extended accordingly. The existence of static electricity in screen printing can cause many quality problems, and even make printing unable to continue. How to avoid and eliminate static electricity in screen printing?
First of all, it is controlled from the process conditions of the screen itself. Under the high tension of the screen, the screen distance is as low as possible. When the screen distance is reduced, the pressure of the scraper will be reduced, and the friction of the scraper on the screen will reduce the possibility of static electricity generation.
Secondly, you can consider using Dorosin ultrasonic humidifier. The complete structure of Dorosin humidification system is compact and has better humidification performance. The diameter of the mist particles is small to ensure the atomization effect. The nozzle will not be blocked and the maintenance workload is small. Perfect functions can be guaranteed under different conditions of use.