There may be many problems in the process of silk screen silicone printing. The following is a summary of these problems and the corresponding solutions:
Printing quality problems
Fonts are wired, hairy, and jagged
Possible reasons: improper humidity and ink viscosity, the gap between the squeegee and the screen is too small to cause damage to the screen, or the screen mesh is too small and the photosensitive glue layer is too thin.
Solution:
Adjust the humidity and ink viscosity of the printing environment.
Accurately adjust the gap between the squeegee and the screen to avoid damage to the screen due to too small a gap.
Use appropriate mesh and thicker photosensitive glue, or use a screen with a large mesh plane or object surface, and use thick photosensitive glue.
The graphics are uneven and the boundaries are unclear
Possible reasons: The squeegee blade is damaged, the ink layer is too thin, the mesh is too small, and the photosensitive glue layer is too thin.
Solution:
Re-grind the blade and install it again.
Thicken the ink layer, change to a fine mesh screen, thin the photosensitive glue and remake the screen.
The edge of the graphic is not clear
Possible reasons: the mesh is too coarse, the photosensitive glue layer is too thin.
Solution:
Adjust the fine mesh screen, thicken the photosensitive glue and remake the screen.
The ink spreads after printing
Possible reasons: the mesh is too coarse relative to the ink viscosity and the graphic.
Solution:
Choose the appropriate mesh according to different inks and different graphics (resolution).
The slurry on the screen cannot be scraped clean
Possible reasons: the squeegee pressure is too small, the printing gap is too large.
Solution:
Increase the pressure and adjust the appropriate printing gap.
Ink adhesion problem
The ink cannot be printed on the surface of the substrate
Possible reasons: the surface of the substrate is not clean, the film layer is too thin, the mesh is too fine, the photosensitive glue layer is too thin, the rubber squeegee is too soft, and the squeegee pressure is too large.
Solution:
Clean the surface of the substrate before printing.
Use coarse mesh or low viscosity slurry, and add the photosensitive glue layer to an appropriate thickness.
Change to a hard squeegee and reduce the squeegee printing pressure.
The substrate is not dry after printing
Possible reasons: The substrate is not fully dried, such as printing just after wiping the solvent and not dry.
Solution:
Wash and dry the substrate under constant temperature before printing.
The ink layer falls off
Possible reasons: The baking temperature of the silicone product after screen printing is too low, the time is short, the ink concentration is uneven, the printing screen is of poor quality, or the printing speed is too fast.
Solution:
Appropriately increase the baking temperature and extend the baking time.
Ensure that the ink concentration is appropriate, use a good quality screen, and appropriately reduce the printing speed.
Other common problems
Single key offset
Possible reasons: Inaccurate positioning during printing.
Solution:
Apply a thin layer of beauty tape on the cover of the jig to assist positioning.
The character surface is not smooth
Possible reasons: The ink is too dry, resulting in increased friction between the ink and the squeegee on the screen.
Solution:
Dilute the ink to a certain extent to improve its fluidity.
To sum up, there are many problems that may arise in the process of screen printing silicone printing, but as long as we master the correct solutions and techniques, we can effectively avoid these problems and ensure printing quality and production efficiency.