① Dust, oil stains and other substances are attached to the surface of the printed matter.

    ② When printing, the ink itself has bubbles or uneven viscosity.

    ③ Printing speed is too fast or uneven.

       The internal factor of bubble generation is that the ink viscosity is high, the ink surface tension is large, and the air oil in the ink is difficult to separate from the ink film and stay in the ink layer. If the ink viscosity is low and the ink surface tension is small, the bubbles will disappear by themselves, so there will be no bubbles in the ink of the printed matter.Remove bubbles on the surface of silk screen substrate.

       Generally, the following measures can be taken to prevent bubbles in the ink layer.Remove bubbles on the surface of silk screen substrate

      ① Use hydrophobic solvents as much as possible.

      ② When the ink itself produces bubbles, an appropriate amount of defoamer can be added to the ink. If the ink fluidity is poor, when the screen printing plate is lifted, the ink flow is relatively small. If the screen trace cannot be filled, there will be no smooth ink layer on the surface.

In order to prevent screen marks after printing, the following methods can be adopted:

      ① Print with liquid ink.

       ② Consider printing with ink with slow drying speed to increase the flow time of ink and make the ink solidify gradually.Remove bubbles on the surface of silk screen substrate

       ③ When making plates, try to use single diameter wire mesh with fine wire diameter.Remove bubbles on the surface of silk screen substrate