The screen printing is a printing plate made by hand engraving or photochemical plate making, using silk fabric, chemical fiber fabric or wire mesh. The screen printing equipment is simple, mainly consists of five parts: screen, scraper, ink, stamping table and substrate. The operation is convenient, the cost is low, and the adaptability is strong. In the screen printing mesh printing process, the ink is transferred by the doctor blade and transferred to the substrate through the grid of the pattern portion to form the same pattern as the original pattern. Screen printing is widely used in general prints: color oil paintings, posters, business cards, binding covers, merchandise signs, printing anddyeing textiles, etc.
The basic principle of screen printing is to use the basic principle of screen printing to penetrate the ink, and the non-imaged portion of the mesh is opaque. The ink is poured onto one end of the screen printing plate during printing, and is moved to the other end of the screen printing plate by a doctor blade to apply a certain pressure to the ink portion on the screen printing plate. During the movement, the ink is squeezed from the grid of the pattern portion onto the substrate by the rubber roller. Due to the viscous action of the ink, the print is fixed within a certain range. During the printing process, the doctor blade is always in linear contact with the printing plate and the substrate, and the contact line moves with the movement of the blade due to the action of the printing plate and the substrate. A certain gap is maintained between them, so that the screen printing plate exerts a reaction force on the blade by its own tension during printing, so that the screen printing plate and the substrate are only in contact on a moving straight line, and the screen printing plate is The other parts are separated from the substrate. The movement of the ink and screen ensures the accuracy of the print size and avoids the smudge of the substrate. When the scraper scrapes across the entire surface, the frit is lifted and the ink is gently scraped back to its original position.
The grid is one of the important materials for making stencils. The choice of photo frame directly affects the quality of the printing plate and the printing effect. In order to ensure the requirements of plate making, printing quality, etc., the photo frame can be selected according to the following conditions.
1. The frame must have a certain strength. This will give the screen a certain amount of tension and pressure on the frame. The frame is also able to withstand pressure, no deformation, and maintain dimensional accuracy.
2. In the case of ensuring strength, try to make the rack light and easy to operate and use.
3. The bonding surface between the grid and the grid should have a certain roughness to strengthen the bonding between the grid and the grid.
4. The frame is strong. The rack is often exposed to water and solvents during use and is subject to temperature changes. This requires the frame not to be tilted to ensure reuse of the frame. Reduce the waste of costs.
5. In the production, different specifications of the grid should be configured. When used, the appropriate border can be determined according to the print size, which is wasteful and easy to operate.
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