Five key points to understand for the best silk sc

Five key points to understand for good silk screen printing technology

1. ink preparation

how to judge the degree of thickening and thinning: the degree of thickening is better if there are no silk lines or wiredrawing on the printing surface after the ink passes through the wire. The best way to dilute the ink is to put it on the silk, and the ink can pass through the hole by its own weight without dripping. When the printing line is thin, it should be thinned, otherwise, it should be thickened

2. select

the quality of silk cloth is stable with uniform silk diameter and accurate mesh number. Generally, 450~500 meshes are selected. For the substrate with fine line, high ink fineness and poor absorption, the version with high mesh number should be selected, on the contrary, the version with low mesh number should be selected. During plate making, the position and size of graphics and text on the plate should be determined according to the structure and size of the substrate and the position of graphics and text on the substrate. If the design is not good, it will affect the quality of silk screen printing, or even unable to silk screen printing. In addition, the oil output of the graphic oil return pipe on the same printed object is large, so it is best to use one plate for printing. If printing is divided into more than two plates, more processes will reduce the screen printing qualification rate

3. Scraper selection

the material of the scraper is mostly polyurethane. The conference on abrasion resistance, solvent resistance and resilience of polyurethane rubber scraper announced that the new members of the 3rd China EU Automotive Materials Committee and the Implementation Council of the Alliance (2014 (2) 016) have good performance. Its hardness is 60~80 shore. For the substrate with large plate tension and good surface flatness, a scraper with high hardness should be selected. On the contrary, there is still a large market space for the development of extruder industry with low hardness. When printing on the substrate with curved surface, low spherical surface or poor flatness (local bulge), the width of the scraper should be narrow rather than wide

4. version positioning

the fixture materials used by the factory include metal, wood, plywood, PVC transparent sheet. If it is difficult to locate and the size of the substrate is small, metal fixtures should be used. If the image and text are close to the edge of the substrate, a flat wood as high as the edge of the substrate should be fixed next to the substrate, so as not to make a similar test paste for the image and text. The distance is generally 1.0~2.5mm. If the printing patterns are easy to paste or have lines, the spacing should be adjusted by average

5. silk screen printing process

high scraping pressure leads to a large amount of ink, but the version 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 ink output is small, but it is not easy to block. Therefore, the printing ink that is easy to block should be scraped faster. There are three kinds of scraping routes: straight line, slash and curve. It should be selected according to the flatness of the substrate and the distribution of graphics and text on the substrate. When the scraping route is long and the ink consumption is large, the scraping amount should be more, or even scrape a layer of ink before scraping