Screen Printing Screen Making Requirements and Process Technology

There are many online platemaking methods, but also have their own advantages and disadvantages. Our current platemaking methods mainly use the indirect method of photolithography. It is the use of chemical changes in the photosensitive paste, that is, the photoreceptor part of the light generated cross-linked hardening and a strong bond with the screen to form a film, the unexposed part is washed through water or other developer developed through holes and made of wire mesh Plate version.

First, we should choose to wipe the screen with the matching version, wash with high efficiency, repeated washing with water, cool and dry for later use. Then, the prepared photosensitive paste is evenly brushed on the screen, the screen is placed in an oven at 60-65° C., and baked for 10-13 minutes. The photosensitive paste is evenly brushed again and dried in the oven. Take out to be exposed, drying time is too long or too high will cause difficult to develop, off the net difficult, on the contrary, the film is not strong, the exposure is not transparent.

Before the exposure, it is necessary to make a check on the bottom plate to see if the edge of the bottom plate is smooth, whether the handwriting is clear, whether there are scratches, dew point, etc., and then use a printing machine for exposure. When placing a photographic plate, it should generally be placed in the center of the net, or it can be placed according to its own actual printing requirements. In order to achieve a good plate edge effect, the angle is generally better than the screen 30 degrees, straight stretch net should be completely perpendicular to the frame, must avoid the holes on the screen and air bubbles and other stains. It is necessary to pay attention to the front and back of the original film in order to prevent the system from being reversed. The most important link in the exposure process is to closely attach the screen to the bottom plate, so as to prevent the drying out of the picture and make it even useless.

In the exposure, the distance between the lamps should be in line with the diagonal of the actual figure of the plate making (for reference), and the time is determined by the fineness of the exposed plate. Using a printing machine (single lamp 2000W) should generally be 80 seconds to 100 seconds is appropriate. The perspective glass should be carefully wiped. The long exposure time is difficult to develop, the short-term film is not firm, and it is easy to fall off during development to form serrated edges.

Development: Immerse the exposed screen plate in water for one or two minutes (30 °C -40 °C warm water is better, shorten the development time), and constantly shake the screen and other unexposed areas to fully absorb water and swell. Rinse with strong water and wait for the graphic to be printed. The development should be completed in a short time. No matter what kind of screen, you must completely wash the unsensitized parts.

The principle of control of the degree of development is: under the premise of revealing and developing, the shorter the time, the better. Too long time, the film wet expansion is serious, affect the clarity of the image, and easy to lose, the film is easy to rotten; time is too short, the development will not be completely ignorant (ie residual glue) caused by waste version. The rest of the glue is a thin layer of photosensitive adhesive residue film. It is easy to appear highly transparent in the details of the image. It is difficult to distinguish, often mistaken for clear, and the ink cannot pass during printing.

After the development, take out the screen plate and blot the screen plate with absorbent paper or newspaper, place it in an oven at 60-65°C, dry it, and take it out. If there are holes or holes that should not be on the plate, use the sealant for proper repair. (Drying time should not be too long, otherwise it will cause difficulty in film removal when the screen is re-used.)