1. Poor pearl effect or no pearl effect
the reason
1. The printing plate mesh hole is too shallow or the mesh hole is clogged, and a dry plate phenomenon occurs.
2. The viscosity of the ink is too high or too low, which does not match the speed of the printing machine.
3. The angle of the ink knife is too large or the pressure of the impression cylinder is too high.
Approach
1. The printing plate net hole is generally 25 ~ 45μm, use thinner to clean the printing plate net hole.
2. Adjust the viscosity of the ink to match the speed of the printing press.
3. Adjust the angle of the doctor blade, generally 45 ° or reduce the pressure of the roller.
Second, sticky back, adhesion
the reason
1. The pearlescent ink on the printed matter is not completely dried.
2. The coil tension is too large or the coiling length is too long.
3. Improper treatment of film corona or moisture.
Approach
1. Add quick-drying thinner to the ink, or increase the power of the drying device to make the ink dry completely.
2. Reduce the winding tension and shorten the curling length.
3. Reprocess the film and prevent moisture.
3. Uneven printing of pearlescent ink
the reason
1. The viscosity of pearlescent ink is too high, it is not easy to coat evenly, and the unevenness of the ink layer is caused after imprinting.
2. Pearl powder is easy to precipitate.
3. Poor contact between the impression cylinder and the plate cylinder.
4. The proportion of pearlescent powder in the pearlescent ink layer is insufficient.
Approach
1. Reduce the viscosity of the ink and choose a suitable thinner.
2. Fully stir the pearlescent ink.
3. Increase the pressure of the impression cylinder or replace it with a new cylinder.
4. Choose high-quality pearl powder and dilute agent to make pearl powder account for 30% ~ 35%.
Fourth, there is a pearlescent effect but dull
the reason
1. The evaporating speed of the thinner is too fast.
2. The oven temperature is too high or the cold air is too large.
3. The viscosity of pearlescent ink is too low.
Approach
1. Slow-drying thinner should be added to adapt to the speed of the printing press.
2. Reduce the oven temperature or reduce the amount of cold air.
3. Increase the viscosity of pearlescent ink and adjust with the same gold oil.
Fifth, the knife line often appears
the reason
1. The squeegee has a gap or an incorrect angle.
2. The pearl ink is not fine enough or the viscosity is not suitable.
3. The printing plate is too deep.
Approach
1. Replace the squeegee or adjust the squeegee angle to scrape off excess ink on the layout.
2. Adjust the viscosity of the ink to match the speed of the printing press.
3. After the printing plate, add two cold air ducts to blow the plate.
Six, paste version, blocking version
the reason
1. The ink dries too fast.
2. Impurities are mixed.
3. The angle of the doctor blade is inaccurate or the distance from the impression cylinder is too large.
Approach
1. Add the corresponding thinner to the ink.
2. Pay attention to the surrounding environment and control the humidity in the workshop.
3. Adjust the distance between the squeegee blade and the impression cylinder to reduce the drying time.
7. Pearlescent powder is inconsistent before and after printing
the reason
1. The color change of pearlescent ink occurs.
2. The pearlescent effect is inconsistent.
3. Uneven mixing and accumulation of pearl powder.
Approach
1. Control the drying of the first few colors of ink to prevent the first few colors of ink from mixing into the pearlescent ink and causing color change.
2. The diluent should not be added to the ink pump separately, and should be added together with the pearlescent ink.
3. When stirring with the ink pump, the accumulation of pearlescent powder should be cleaned in time to prevent uneven coating.
8. Poor peel strength after printing compound
the reason
1. The film corona treatment does not meet the requirements.
2. Adhesives and thinners are not compatible with pearlescent inks.
3. Uneven gluing amount during compounding.
Approach
1. Grasp the film variety and the standard of corona treatment.
2. Choose pearlescent ink to make it compatible with the adhesive.
3. Control the amount of glue, temperature and tension during compounding.
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