The first point. Stretching the net
Stretching steps: net frame cleaning--horizontal calibration--applying bottom glue--pulling the net--testing tension--applying glue--down the net, edge banding--storage
Job description:
1. Due to the repeated use of the screen frame, there are residual glue, gauze and other sundries around the screen frame, which must be removed to avoid affecting the adhesion between the gauze and the screen frame.
2. Place the screen frame on the platform (horizontal) to check whether the screen frame is deformed, and if it is deformed, it needs to be leveled.
3. Clean up the undeformed screen frame and the mesh and apply a layer of glue without hardener evenly on the surface to enhance the adhesion between the mesh and the screen frame after pulling the net.
4. About 10 minutes after the first glue application, place the screen frame on the stretching table, and adjust the relative position and height
5. Select the mesh, loosen the clamps around the mouth, spread the mesh on the frame, and then clamp the mesh evenly into the clamps, there should be no wrinkles, pay attention to the loose mesh at the four corners, the clamps must be It needs to be locked tightly, and there should be no gap between the clips (for example, automatic lifting frame and manual pulling net).
6. Stretching net: the first tension is 26, and the tension is 24 after standing for 5 minutes; the second tension is 28, and the tension is 26 after standing for 5 minutes; the third tension is 32, and the tension is 30 after standing for 5 minutes; the fourth correction Tension at 5 points is 32, gluing tension is 30 after standing for 20 minutes; screen tension is 28 after glue curing for 15 minutes, and screen can be made after standing for 72 hours (take the screen of a one-meter×one-meter automatic production line as an example). Pull it vertically and horizontally synchronously, and brush the glue when it reaches the required tension. The tension of the commonly used mesh yarn is (30±2 Newton for 100T, 110T, 120T) (35±2 Newton for 77T, 51T) (35±2 Newton for 24T) 50±2 Newton)
7. Use a small brush to evenly brush the adjusted glue on the joint surface between the screen frame and the mesh. Do not drop the glue into the middle part of the screen. After the glue dries for 8 minutes, use a scraper to glue the unglued surface on the glued surface. The place that fits perfectly should be pressed tightly for about 10 minutes before the glue is completely dry (open blowing should be used to strengthen the drying) before the net can be released.
8. Use a paper cutter to remove the excess mesh around the screen, and mark the date, mesh and tension on the screen frame (in order to observe the tension change) in order to prevent the infiltration of washing water (anti-white water). The inner corners of the screen frame are sealed with red glue, and then sealed with waterproof tape on the joint surface between the screen frame and the mesh to prevent the infiltration of the liquid medicine.
The second point. Posting on the net
1. Net washing: use grinding cream to remove grease (new net), ghost cream to remove graphics (old net), desizing powder to remove net pulp and blue oil, wash sundries with anti-white water, rinse net with detergent, and finally Rinse it with a high-pressure water gun, and finally rinse it with pure water. the
2. Drying: --The setting temperature of the oven should be less than 48 degrees Celsius.
3. The method of using affixed film: wash the clean net and then wash it with pure water again. Select the water film according to the increase of about 20% in the project film patchwork pattern, press the end of the water film on the net with a triangle ruler, then use the triangle ruler to slowly scrape it upwards, then use a rubber scraper to gently press and scrape it, and wipe off the excess water with a towel parts dry.
4. Use photosensitive adhesive (net pulp): dry the screen and then apply photosensitive adhesive, use a scraper box to scrape it onto the net, among which the silk screen green oil needs to be sizing three times, (about once every 10 minutes or more) silk screen printing other anti-corrosion The ink is used twice, and the screen printing peelable glue (blue glue) is first coated with 50 micron water film to tear off the film, and then the net pulp is applied twice, scraped three times each time, and dried after the sizing is completed.
5. Mesh selection The general line includes screen printing of character inks, and anti-corrosion inks (green oil, base oil, top oil) with 120T, 100T, 110T mesh, carbon paste (carbon oil) 51T, silk screen can be stripped ink (Blue glue) 77T for 24T silk screen photosensitive circuit and thermal curing ink.
6. Film selection: use 18K water film for the line (do not use photosensitive glue, use photosensitive glue to surf the Internet, it will easily cause unevenness: such as rough edges (dog teeth) and other problems), other anti-corrosion inks (green oil, base oil, surface oil) use photosensitive Glue (net pulp), carbon pulp (carbon oil) use 50 micron water film
7. Paste the required engineering graphics film on the selected position of the screen, and place it on the exposure machine for exposure. The selection of time (3000W spotlight), the line is generally 60-80 seconds, the green oil is 80-100 seconds, and the character oil on the bottom surface 40-60 seconds, carbon oil, blue gum 350-400 seconds
8. Rinse the net with pressurized water and dry.
9. After the stencil is made, use the sealing glue (blue oil) to cover the place on the screen that is not covered by film or photosensitive glue, scrape the sealing glue with a silk screen scraper, and dry.
10. Check, repair the network, write the date of completion and the corresponding numbers, and record and store them.
The third point. Storage
Generally, vertical storage is used for storage. You can make your own or buy a screen frame. It needs to be stored in the same environment as the screen printing environment to prevent deformation. At the same time, the tension of the screen needs to be tested before screen printing, and the graphics can be inspected with photographic negatives.
