Several technical points of screen printing machine printing

Screen printing machine is a large-scale equipment in the printing industry. It has been widely used in our life and work. Except for liquid and air, almost everything can be printed with screen printing machine. The adjustment and control of the screen distance of the screen printing machine during printing is one of the important factors affecting its quality. The silk screen printing operator of the screen printing machine will make corresponding adjustments to the screen printing screen distance of the screen printing machine in order to ensure the printing quality.

as follows:

1. The key to the printing process of screen printing machines

　　If the scraping pressure is high when the screen printing machine is printing, the amount of ink will be large, but the screen plate is easy to deform, so the scraping pressure should not be high. The scraping speed is usually 60~200mm/s. The scraping speed is fast, the amount of ink output is small, but it is not easy to block the screen. Therefore, for the ink that is easy to block the net, the scraping speed should be faster.

　　When the screen printing machine is printing, the scraping path should be straight line, oblique line and curved line. It should be selected according to the flatness of the substrate and the distribution of graphics and text on the substrate. When the scraping path is long and the ink consumption is large, the amount of scraping ink should be more or even scrape a layer of ink first, and then scrape.

　　2. Ink manufacturing before printing by screen printing machine

　　How to judge the degree of thickening and thinning: after the ink passes through the screen, the degree of thickening should not appear on the printing surface. The degree of thinning is best to put it on the screen, and the ink can pass through the mesh by its own weight without dripping. When the printed line is thin, it should be thinned, otherwise, it should be thickened.

　　3. Selection of printing squeegee for screen printing machine

　　The raw material of the scraper is mostly polyurethane. Polyurethane rubber scrapers have better wear resistance, solvent resistance and resilience. The hardness is 60~80 Shore. For substrates with large screen tension and good surface flatness, scrapers with high hardness should be used. On the contrary, low hardness should be used.

　　When printing on curved surface, low-degree spherical surface or substrate with poor flatness (partial protrusion), the width of the scraper should be narrow rather than wide.

　　4. Selection of screen before printing by screen printing machine

　　The quality of silk cloth is stable in quality with uniform diameter and precise and consistent mesh number.

　　The generally selected mesh is 450~500 mesh. For substrates with thin lines, high ink fineness, and poor absorbency, a screen with a high mesh number should be used; otherwise, a screen with a low mesh number should be used.

The position and screen size of the graphics and text on the screen during plate making should be determined according to the structure and size of the substrate and the position of the graphics and text on the substrate. If the design is not good, it will affect the quality of silk screen printing, or even fail to screen printing. In addition, it is best to use one screen printing for the graphics and text on the same printed matter. If divided into two or more screen printing, more processes will reduce the pass rate of screen printing.