I believe that most screen printer operators know that when the screen printer is printing, bubbles sometimes appear on the ink after printing on the substrate. This is a common problem during printing. Experienced operators know the problem. Wherever you are, you can avoid the generation of bubbles, but there are also new operators who do not know how to solve the bubbles during printing. Here is a small editor to share with you the reasons for the bubbles during printing:
1. Poor pre-print processing of the substrate
The substrate must be kept clean before printing, because the surface of the substrate is easy to adhere to dust and oil stains.
2. The printing speed is too fast or the printing speed is uneven
During printing, the printing speed can be appropriately reduced to maintain the uniformity of the printing speed.
3. Wrong proportion when adjusting ink
When adjusting the ink, the proportion of defoamer added is wrong. The amount of defoamer added in the ink is generally about 0.1 to 1%. If it exceeds the specified amount, it will have a foaming effect.
4. Pay attention to transparent inks such as red, blue, and green
For transparent inks such as red, blue, and green, because the proportion of organic pigments in the particles is small, the binders of these inks have the characteristics of easy foaming. If the corresponding diluent, tackifier or remover is added, the ink can also be transformed into a stable ink with good printability.
Even if the ink of the screen printing machine foams after the transfer, as long as the substrate is wet and the ink fluidity is good, the bubbles on the surface of the printing ink film will gradually disappear, and the ink will form a flat printing ink film. If the ink bubbles are not eliminated, the ink film will form a ring-shaped uneven film surface. Generally, when the bubbles in the ink pass through the screen, they can be defoamed due to the effect of the screen. In addition, hot water or boiling water will have a better defoaming effect when the ink is mixed and stirred.