There are many reasons why bubbles are generated when printing with screen printing silicone. Here are some of the main factors:
Poor fusion between silicone and fabric: When printing, the ink fails to fully penetrate the fabric, and the silicone covers the surface of the fabric. When baking, bubbles will be generated, resulting in defects such as bubbling and pores on the surface of the fabric.
High viscosity of silicone: When the silicone is more viscous, its leveling performance will be reduced, causing small bubbles to gather in the silicone. Once the temperature rises, these bubbles will float up, affecting the printing effect.
Surface contamination of the substrate: If the surface of the substrate to be printed (such as fabric) is not cleaned, there are impurities such as dust and oil stains, which will affect the adhesion of the silicone screen printing ink, resulting in the generation of bubbles.
Ink quality problems: The silicone ink used may have quality problems, such as expiration and ineffectiveness, and unequal viscosity, which may cause bubbles during printing.
Poor printing environment: Using quick-drying solvents in a high temperature and low humidity environment may cause the surface of the ink to conjunct too quickly and cause bubbles. In addition, if there is dust and debris in the printing environment, it may also affect the printing effect.
Printing process problems:
The shape of the squeegee is not suitable: If the scraper of the squeegee is too flat or the arc is not right, bubbles may also be generated.
Excessive or uneven printing speed: Excessive or uneven printing speed may cause the ink to fail to fully wet the surface of the substrate, resulting in bubbles.
Improper distance between the screen and the substrate: The distance between the screen and the substrate is too large, which may cause bubbles to be pulled out when the screen bounces off the substrate.
In order to solve the problem of bubbles generated during screen printing of silicone, the following measures can be taken:
Reduce the viscosity of the silicone: Reduce the viscosity of the silicone by adding diluent to dilute the ink, improve the leveling performance, and reduce the generation of bubbles.
Clean the substrate surface: Before printing, ensure that the surface of the substrate to be printed is clean, dust-free and oil-free to improve the adhesion of the ink.
Select the right ink: Select silicone ink of reliable quality and adjust the viscosity of the ink according to printing needs.
Optimize the printing environment: Control the temperature and humidity of the printing environment, avoid using quick-drying solvents or printing in a high temperature and low humidity environment.
Adjust the printing process: replace the appropriate scraper, adjust the printing speed and pressure, control the distance between the screen and the substrate, etc. to reduce the generation of bubbles.
In summary, there are many reasons for the generation of bubbles during screen printing silicone printing, which requires comprehensive analysis and solutions from multiple aspects such as ink, substrate, printing environment, and printing process.