Silk screen silicone printing is a highly technical process. Its operation points involve multiple links, which need to be strictly controlled to ensure the printing quality. The following are the specific points:
1. Preliminary preparation
Equipment and material preparation
Tray screen printing machine: including frame, fixture, printing head, etc., to ensure the normal operation of the equipment.
Silicone printing plate: Choose a silicone printing plate of suitable material and thickness to ensure good contact between the printing plate and the printing material, and the surface of the printing plate is flat without bumps or damage.
Printing materials: such as flat objects such as plastic, glass, and metal, the surface must be clean and free of debris.
Printing ink: Choose the appropriate ink type and color according to the needs. Silk screen ink can be used, and its viscosity is generally between 4000 and 12000 centipoise.
Scraper: used to scrape off excess ink.
Other tools: such as electronic scales, glue knives, glue containers and other glue mixing tools, as well as 407 printing water or white oil and other materials for thinning and washing screens.
Mold treatment
If a mold is used, it needs to be cleaned to ensure that there is no moisture. It can be wiped with a dry cloth or blown dry with an air gun, and finally a layer of release agent is applied.
2. Glue adjustment and color adjustment
Glue adjustment and dilution: Mix the silicone and diluent in a certain proportion, such as mixing 150 grams of silicone with 150 grams of diluent, and stir evenly until it becomes a bright liquid glue. For textile screen printing silicone, if the lines are thick and the printing is thick, the addition ratio of embossed silicone and diluent can be 1:1.3; if the lines are thin and the printing is thin, the addition ratio of liquid silicone and diluent can be 1:0.90.
Color glue: Add an appropriate amount of color paste to the diluted silicone, stir it thoroughly to obtain the silicone of the desired color. The general amount of color paste is 5% - 8%, and gold and silver powder can also be added as needed.
3. Printing operation
Install the printing plate: Fix the silicone printing plate on the printing head of the walkway screen printing machine to ensure good contact.
Adjust the equipment: adjust the height of the workbench of the walkway screen printer so that the contact surface of the printing material and the silicone printing plate fit closely; adjust the fixture to fix the printing material to avoid movement or shaking.
Prepare ink: Pour the required ink into the ink tank, add diluent as needed to adjust the ink viscosity, and avoid ink splashing or excessive.
Apply ink: Place the scraper flat on the silicone printing plate, apply the ink evenly to the blade edge, and ensure that the ink is evenly distributed on the silicone printing plate.
Printing operation: Slowly move the printing head on the walkway screen printer to let the silicone printing plate contact the printing material, use appropriate pressure and speed to transfer the ink on the silicone printing plate to the surface of the printing material, and use manual or automatic control of the printing process.
Multiple printing: Multiple printings can be performed as needed to increase the ink thickness and color saturation. After each printing, scrape off the excess ink on the silicone printing plate with a scraper, and adjust the printing position and printing head pressure as needed.
4. Subsequent processing
Drying and molding: After printing, dry naturally at room temperature of 15-35 degrees, or heat and dry when it is below 5 degrees, and control the temperature at about 30 degrees. For clothing silk screen printing silicone, the general temperature is about 120-160 degrees Celsius.
Clean up after work: pour out the unprinted silicone on the screen, gently wipe the screen with a thinner to prevent clogging of the mesh; remove the printed material from the workbench, clean the silicone printing plate, use appropriate cleaning agents and soft cloth to avoid damaging the silicone printing plate, dry it after cleaning, and store it in a dry place.
5. Precautions
Ink and substrate: The ink should be properly mixed, and the surface of the substrate should be clean and free of debris to ensure the silk screen effect.
Selection of rubber head: Replace the appropriate rubber head according to the scale of the pattern. Use a large silk screen rubber head for large-scale patterns and a small rubber head for small-scale patterns. The ratio between the rubber head size and the pattern is generally 3:1.
Temperature and time: After the screen printing is completed, pay attention to the baking temperature and time to avoid poor wear resistance of the pattern and discoloration due to low temperature or short time. Screen cleaning: Textile screen printing silicone is easy to plug the screen. Wash the screen with oil water (thinner) every 3-4 hours, or wipe the screen with oil water before leaving get off work, and place it in a ventilated place to dry naturally for the next use.