How to solve the problem of the screen printing mesh in use? (2)
1. Ink unevenness or color bars appear in printing screen mesh
Analysis of the cause: During the printing process, the pattern printed on the substrate sometimes has inconsistent color depth or regular color bar failure on the pattern. The reason for the above-mentioned faults is analyzed, mainly because the printing speed is not uniform, and the pressure applied on the squeegee is different, which causes the amount of ink leakage in the screen to be reduced or decreased. Therefore, the marks formed on the substrate are suddenly deep and shallow: Secondly, due to the inconsistent bending angle of the scraper, the printing pressure is also inconsistent, resulting in the difference in the amount of ink leakage in the screen, thus forming different patterns on the substrate; in addition, because the screen printing plate is not smooth or the printing table is not Flattening also causes the squeegee to bounce in the printing of the substrate, forming a color bar failure on the substrate.
Troubleshooting: According to the above analysis, carefully check the cause of the failure, and take measures to eliminate it. For example, when the squeegee is pressed and printed, the bending angle is different, and the printing pressure is different. Therefore, when the pressure is large, the pattern is dark, and the pressure is small, and the pattern color is shallow, and the ink is uneven. At this time, it is necessary to re-adjust the pressure of each color squeegee so that the inclination angle is uniform and the applied pressure is uniform. Then start printing, and the fault of uneven printing on the substrate pattern can be eliminated.
2. A ghost image appears on the screen printing substrate
Analysis of the cause: When printing on a screen printer, the phenomenon that the image on the substrate partially or completely exhibits a double image is called a ghost failure. Especially small areas of images and lines are more obvious. The reason for this kind of ghosting failure is that the tension of the tensioning net is insufficient, and the layout is slack. When the pressure in the running of the squeegee is slightly larger, the layout is slacked before the cutting edge of the squeegee running direction, and the image on the layout is accompanied by Shifting, the image printed on the substrate has a ghost image: the plate locator is too large with the gap or the positioner is not fixed. When the squeegee is running, the plate moves forward, causing the plate to move forward. The positioning of each color is inconsistent during printing, which makes the image on the substrate appear ghost: when the first time of printing, the substrate does not get a full pattern, so that the image is not clear, when the second repeated printing, due to printing The displacement of the plate or substrate may also cause ghosting failure; the artificial leather or plastic cloth padding on the printing pad is not tight enough, and the pressure of the blade is high, so that the artificial leather or plastic cloth is generated before the blade in the running direction of the blade. Relaxation forces the substrate placed on the pad to move, thus creating a ghost image in the print.
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