It is not an exaggeration to compare the PCB screen printing to the outerwear of the PCB board. As the saying goes, people rely on clothing, so having a good-looking appearance is the most intuitive experience for users to look at the printed board. Users will comment on a board because of its appearance. In addition, the silk screen solder mask and characters are the post-processes in the lengthy manufacturing process of the printed board. The printed board that is about to be completed with a high value has errors in the post-process, and the loss is too large. It's not worth it. Besides, solder mask and characters are one of the processes with the largest amount of scrap. Therefore, it is very important to stabilize the process of screen printing solder mask and characters, and straighten out the management of this process, document control and equipment maintenance.

After 1990, basically all PCB supplier china did not use traditional craftsmanship. There are reasons for this, including: the density of double-sided and printed boards is increasing. The high density of small holes and fine lines SMT is an irreversible trend in the development of printed boards. The line width spacing is 0.12~0.20mm narrow welding. The ring is already in the majority, and the silk-screen thermosetting green oil is powerless, the appearance is not neat, the oil is leaked on the pad, and the printing is too much affected by the proficiency and emotions of the silk-screen employees. Therefore, most of the current double-sided and multilayer board factories All have eliminated the thermosetting epoxy green oil and switched to the liquid photosensitive solder mask process.