What are the aspects we need to pay attention to for screen printing?
Screen printing mesh is to stretch silk fabric, synthetic fabric or wire mesh on a frame, and make a screen printing plate by hand-engraving film or photochemical plate making. The modern screen printing technology uses a photosensitive material to make a screen printing plate by photolithography (so that the screen hole of the graphic portion on the screen printing plate is a through hole, and the non-graphic portion of the wire mesh hole is blocked. live). During printing, the ink is transferred to the substrate through the mesh of the graphic portion by the extrusion of the squeegee to form the same graphic as the original. The screen printing equipment is simple, easy to operate, simple in printing and plate making, low in cost, and strong in adaptability. Screen printing applications are widely used in common prints: color oil paintings, posters, business cards, binding covers, merchandise signs, and printing and dyeing textiles.
Screen printing consists of five major components, namely screen plates, squeegees, inks, printing stations, and substrates. The basic principle of screen printing is to use the basic principle of the screen printing plate to penetrate the ink, and the non-image part of the mesh is not transparent. The ink is poured on one end of the screen printing plate during printing, and a certain pressure is applied to the ink portion on the screen printing plate by the squeegee blade while moving toward the other end of the screen printing plate. The ink is squeezed from the mesh of the graphic portion onto the substrate by the squeegee during movement. Due to the viscous action of the ink, the print is fixed within a certain range. During the printing process, the squeegee is always in line contact with the screen printing plate and the substrate, and the contact line moves with the movement of the squeegee due to the screen printing plate and the substrate. A certain gap is maintained between them, so that the screen printing plate at the time of printing generates a reaction force against the squeegee by its own tension, and this reaction force is called a resilience force. Due to the resilience, the screen printing plate and the substrate are only in a moving line contact, and the other portions of the screen printing plate are separated from the substrate. Breaking movement of the ink and the screen ensures print dimensional accuracy and avoids smuddy substrates. When the scraper scrapes across the entire surface, it is lifted, and the screen plate is lifted, and the ink is gently scraped back to the original position.
What are the conditions for selecting a frame?
The frame is one of the important materials for making screen plates. The choice of frame selection has a direct impact on plate quality and print quality. In order to ensure plate making, print quality and other requirements, the frame can be selected according to the following conditions.
1 The frame must have a certain strength. Because of the tension, the screen produces a certain amount of tension and pressure on the frame. This requires the frame to withstand pressure, can not produce deformation, and maintain the frame size accuracy.
2 Under the condition of ensuring the strength, the frame should be as light as possible, which is convenient for operation and use.
3 The mesh frame and the mesh bonding surface should have a certain roughness to strengthen the adhesion between the wire mesh and the mesh frame.
4 frame is rugged. The frame is often in contact with water and solvent during use, and is affected by temperature changes. This requires that the frame does not be skewed to ensure repeated use of the frame. This reduces waste and reduces costs.
5 In the production, different specifications of the net frame should be configured. When using, the appropriate frame can be determined according to the size of the printing size, which can be wasteful and easy to operate.
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