Automatic screen printing machine electrostatic phenomenon and its performance
In the screen printing, when the net template is bounced off the substrate, the ink in the pattern portion of the screen will also be pulled up and floated from the substrate by the flesh-shaped "spider". When the screen version continues to rise, the "spider silk" is scattered on the substrate before and after the wind drifts, so that the surface of the substrate is dirty and the edges of the pattern are not sharp. This is an electrostatic phenomenon of a fully automatic screen printing machine.
What is the static electricity?
From the atomic point of view: all neutral materials, such as plastics, paper and other insulators, that is, the positively charged nuclei in each atom and the negatively charged electron cloud in the surrounding, when the materials are separated by frictional contact, in the insulating material The electrons are released to the surface of the material. For example, in the middle school physics, the glass rod is rubbed with silk, and static electricity generated on the glass rod can suck up the paper scraps. The surface of the electron-reduced material is positively charged, and the surface of the material with excess electrons added by electrons is negatively charged. If the material with reduced electrons is supplemented with negative electricity and the material with increased electrons is positively charged, then the positive and negative charges of the two materials are balanced. Then the two materials are neutral.
In optical disc printing, so-called silk printing is a process of transferring ink onto a substrate under a certain scraping pressure by relative movement of the screen and the squeegee. The screen (screen) and the squeegee (polyurethane squeegee) are all insulators. In the silk screen, they are relatively scraped and rubbed at the position, especially in low humidity, which will cause static electricity to affect the surface charge of the substrate. Distribution status. In particular, insulating materials, such as PC substrates for optical discs, PET sheets for touch-opening, and PVC for plastic and plastic bottles, PEs, etc., which are used for name and sign, are basically insulators, and do not pay attention to static electricity during silk screen operations. Will happen. For example, when the silk screen switch is used to decorate the ink, the surface of the PET film is coated with a layer of PVC and other self-adhesive film to protect the surface, so that it is not scratched in the cutting and packaging. However, the protective film must be removed before silk screen printing. Some operators often peel off the protective film when the film is peeled off. I don’t know that the film is quickly separated from the PET film at the moment of quick film uncovering. In the process, static electricity is generated especially on the surface of the PET sheet under low humidity, and as a result, the ink on the edge of the silk screen has flying hair, and the quality of the fluffy ink on the transparent PET sheet, etc., has been a problem. There is a lot of confusion about the screen printing shop of the membrane switch unit.
In the screen printing, the production difficulties caused by static electricity, etc。, are manifested in the screen printing:
1. After the silk screen is printed, the ink on the print is pulled up in a plush shape along with the screen. After the workpiece is taken out, the phenomenon of "flying hair" is broken.
2。 When overprinting, the first color and the latter color ink edge and the pattern edge are mutually exclusive, which cannot be well matched, so that no ink can be printed between the two color inks。
3. In the silk screen, the workpiece sticks to the screen, especially to the screen position where the scraper moves to the end.
4. The printing materials are inseparable and inseparable
5。 During the squeegee process, the ink is flattened on the screen and the cakes stick together。
6。 The substrate absorbs dust, and the ink is damaged after the silk screen, pitting, rough surface, etc。