The common faults, causes and solutions in the use of screen printing screen are shown in the table.
Common malfunctions | cause | Solution |
pinhole | ①Poor silk screen degreasing, dirty deGraduation ②The bottom plate is not clean, and there is dirt on the printing glass ③Glue application speed is too fast ④ Bubbles or dirt in the emulsion ⑤ There is water on the screen fiber, poor drying and insufficient exposure ⑥The thickness of the film is not enough and the photosensitive glue fails | ①Clean the screen with a good quality cleaning agent ②Remove the dust and dirt on the positive picture and the glass of the vacuum shelf, and check whether there are scratches on the glass ③Squeeze glue slowly and evenly, after each stroke, the screen turns 180° ④Stir and mix the emulsion evenly to make the air bubbles escape, and filter to remove the dirt ⑤At the specified temperature, effectively dry the screen ⑥Increase exposure time and conduct exposure test ⑦Increase the number of gluing ⑧Replace new photosensitive glue |
Poor adhesion between photosensitive film and screen | ①Poor silk screen degreasing, dirty deGraduation ②Drying time is not enough ③Poor flushing ④ Underexposure ⑤Uneven coating ⑥Uneven mixing of colloid and photosensitizer, and the emulsion is left for too long | ① Clean the screen with good quality cleaning agent ②Effectively dry the screen at the specified temperature ③ Control the flushing temperature according to the instruction of photosensitive adhesive ④Increase the exposure time and carry out the sunlight test ⑤Increase the tension of the screen, and apply the glue evenly with the squeegee ⑥ Stir and mix evenly, and check the ratio, and check the storage period specified by the manufacturer |
| Difficulty developing | ①The exposure time is too long ②After scraping the glue, store it for a long time ③The drying temperature is too high ④The photosensitive adhesive has been exposed ⑤When printing the plate, the contact between the bottom plate and the film is not real ⑥ photosensitive adhesive failure ⑦ Diffraction of light during exposure | ① Conduct exposure test and adjust exposure time ②Shorten storage time ③Control the drying temperature according to the instruction ④ Check the lights in the operating room ⑤ Use vacuum adsorption or other methods to make them in close contact ⑥Replace photosensitive adhesive ⑦ Use colored screen |
| residual film | ① The interval between photosensitive emulsion configuration and use is too long ② Uneven coating ③The drying temperature is too high ④ Improper selection of exposure light source ⑤ Underexposure or overexposure ⑥The contact between the negative film and the film is not real when printing the plate ⑦The black and white contrast of the base version itself is small ⑧ Insufficient developing time ⑨The developing temperature is not suitable | ①Shorten storage period ②Increase the tension of the screen, and evenly apply the glue with a squeegee ③ Control the drying temperature according to the instruction of photosensitive adhesive ④ Reasonable selection of light source, preferably strong ultraviolet light ⑤ Conduct exposure test and adjust exposure time ⑥Use vacuum adsorption or other methods to make them in close contact ⑦ Check the clarity and contrast of the bottom plate ⑧Increase developing time ⑨ According to the instructions for use, control the temperature of the developer |
| sawtooth phenomenon | ①Improper selection of screen mesh ② Underexposure ③The film thickness is not enough ④ Diffraction of light during exposure ⑤ Uneven stretching tension ⑥Water pressure is too high when developing | ① Replace the appropriate screen according to the graphics ② Conduct exposure test and increase exposure time ③Apply evenly to increase the thickness of the glue layer ④ Use colored screen ⑤ Improve stretching tension and uniformity ⑥Reduce flushing pressure |
The plate film is cracked and the service time is shortened | ①Poor silk screen degreasing, dirty deGraduation ②Deformation of the wooden screen frame ③The screen tension relaxes, and the photosensitive film surface produces unbalanced shrinkage ④ The drying temperature is too high, causing the screen to deform ⑤ Film thickness is not enough ⑥Insufficient ink fineness or foreign matter ⑦Mechanical friction ⑧ improper solvent, react with photosensitive adhesive ⑨ Underexposure ⑩The quality of the ink is poor, it dries quickly on the screen, and the plate is washed too much ⑪The pressure of the scraper is too high when printing dramas | ① Clean the screen with a good quality cleaning agent ②Replace with aluminum screen frame ③Increase the stretching tension ④ Control the drying temperature according to the instruction of photosensitive adhesive ⑤Apply evenly to increase the thickness of the glue layer ⑥Continue to grind the ink and use it after filtering ⑦ When washing the plate, use softer items to scrub ⑧ Pay attention to the matching of solvent and photosensitive adhesive ⑨ Conduct exposure test and increase exposure time ⑩ Improve the quality of ink, avoid drying too fast, reduce the number of wipes ⑪Reduce the pressure of the scraper and grind the rubber strip of the scraper |
| Low resolution, loss of subtle layers | ①When printing the plate, the contact between the bottom plate and the film is not real ② The bottom plate (positive picture) is of poor quality ③ The quality of the photosensitive glue itself is poor and the resolution is low ④ Improper selection of light source ⑤ mesh number is too low ⑥ Improper processing of developing and flushing | ①Use vacuum adsorption method or other methods to make them in close contact ② Check the film density and image quality ③ Use high-quality photosensitive glue ④ Use a light source corresponding to the spectral sensitivity of the photosensitive adhesive ⑤Select high-mesh screen ⑥ Check the developing and rinsing procedure, adjust the water temperature |
poor edge definition | ①When the base plate is in bad shape, the contact between the base plate and the film is not real ② developing and flushing is not enough ③ Diffraction of light during exposure ④ Uneven coating of photosensitive film ⑤ The screen mesh size is too low compared to the image | ① Use vacuum adsorption or other methods to make them in close contact ②Rinse the screen from both sides until it is clean and clear ③ Use colored screen ④ Check the coating process and increase the tension of the screen ⑤ Select high-mesh wire |
