Key points for improvement of plexiglass screen printing process

Mastering high-quality plexiglass screen printing technology is an important technical force for plexiglass processing plants. The main points for improvement of the plexiglass screen printing process are as follows:

1. A basic requirement for perfect image reproduction is that the quality of the transparent positive film should be good, that is, the edges of the dots should be neat and opaque. The color separation film and the printing ink used use the same color scale.
   

2. The positive image film is placed on a glass plate with plexiglass, and then exposed. The stretched screen is placed on the positive image film, parallel to the image axis. If moire patterns appear, rotate the screen to the left or right until the moire patterns disappear, generally turning 7°. The area where the moire is easily formed is located in the direction of the wire mesh and the intersection of the wire mesh. Main colors and darker colors cause more problems with moire.

3. For four-color printing, aluminum screen frames of the same size and stability should be used, and all screen frames used are stretched with screens of the same type and model. The use of dyed screens helps to eliminate the moiré. The tension of the screen should be uniform and the tension of the four screens of the four-color printing is the same.

4. A well-ground squeegee is very important for high-quality printing. The Shore hardness of the blade is about 70. The squeegee should be set at an angle of 75°. If the angle of the squeegee is adjusted too flat, the printed image may be blurred. If the angle is adjusted too steep, the risk of screen-printed image distortion is high.

5. The ink-returning knife should not be installed too low. If so, the film will be filled with excessive ink, and the printed matter will be easily blurred and smudged.

6. The screen tone image is printed with high-viscosity ink. The finer the screen, the thicker the ink is needed.

7. When using UV ink, the hue range of the screen image should be 5% to 80%, and the Shore hardness of the squeegee should be 75. In order to control the UV ink of Tianjin plexiglass processing without smudging during color overprinting, it is recommended to print in the color sequence of cyan, magenta, yellow, and black. When using UV ink, the screen thickness should not exceed 5um.