In screen printing products, a common problem is the jagged edges of the printed ink film (including incomplete or broken lines). There are many reasons for the burrs, but the main reason lies in the quality of the screen printing plate itself.
① The resolution of the photosensitive glue is not high, resulting in broken or incomplete fine lines.
② Insufficient exposure time or too long exposure time, insufficient development, the edges of the screen printing image are not neat and jagged. For a good screen printing plate, the edges of the image should be smooth and neat.
③ The screen printing surface is uneven. When printing, there is still a gap between the screen printing and the substrate. Due to the suspended penetration of the ink, burrs appear on the edge of the printed ink.
④ During the printing process, the plate film expands after contacting the solvent, and the expansion degree in the warp and weft directions is different, which makes the surface of the plate film uneven. When printing, the contact surface between the screen printing plate and the substrate appears locally: gap, ink suspended penetration, and burrs appear on the ink film.
To prevent the appearance of jagged hair carving, the following solutions can be considered:
① Use high-mesh screen for plate making;
② Use photosensitive materials with high resolution for plate making;
③ Make a screen printing plate with a certain film thickness to reduce expansion and deformation;
④ Try to use the oblique stretching method to stretch the screen, and the best angle is 22.5°;
⑤ For fine line printing, try to use the indirect plate making method, because the indirect plate making method is less likely to have burrs;
⑥ During the plate making and printing process, try to control the temperature expansion factor and use photosensitive materials with a small expansion coefficient;
⑦ Improve the quality of plate making, ensure that the surface of the screen printing plate is flat and smooth, and the edges of the screen lines are neat;
⑧ Use a water spray gun to spray the screen printing plate to improve the development effect;
⑨ The distance between the screen and the substrate, the scraper angle, and the printing pressure should be appropriate.