Problems and Countermeasures of the most popular U

2022-09-23
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Problems and Countermeasures of UV sanding ink in printing

1. the sanding feeling is not good, which shows that the concave convex feeling is not strong. Main reasons: ① the filler in frosting ink is improperly selected, and the particle size is too small; ② Improper amount of filler; ③ Improper selection of scraper; ④ Improper selection of wire mesh

solution: according to the sand feeling requirements of the printed matter, the filler with appropriate diameter can be selected; Appropriately increase the amount of filler; Choose a scraper with appropriate hardness. Generally speaking, the higher the hardness of the scraper is, the clearer the printed pattern is, and the lower the hardness of the scraper is, the easier the printed pattern is to have a false edge, resulting in a weakening of the sandiness. At the same time, adjusting the mesh number of the version can also significantly improve the sandiness of the printed sample. Generally speaking, for the same type of frosted ink, the lower the mesh number, the stronger the sanding feeling. 2. The mirror contrast effect is not obvious. Main reasons: ① the gloss of substrate itself is not high; ② The amount of filler added in frosted ink is too large, completely covering the substrate; ③ The matte degree of the filler is not high, resulting in a weak contrast between the mirror substrate and the ink film surface

solution: choose high gloss mirror substrate as much as possible while selecting appropriate filler

3. The surface of the printed matter is gray and not inked. Main reasons: ① improper selection of wire mesh; ② There is oil stain on the surface of the substrate; ③ Frosted ink contains low volatile oily impurities

solution: Generally speaking, for fillers with large particle diameter, if high mesh number of wires are selected, due to small holes, the ink is not easy to pass through or passes little during printing, resulting in uneven inking and graying, while the existence of oil stains makes inking difficult or spots and graying. This situation can be solved by selecting an appropriate version and corresponding cleaning measures

4. plate pasting occurs during printing. Main reasons: ① the viscosity of frosting ink itself is too large; ② The distance is too small; ③ The number of selected wire mesh is too low; ④ The printing pressure is not appropriate

solution: try to reduce the viscosity of the light solid resin in the frosted ink, adjust the distance between the plate and the substrate, select the appropriate number of wires or adjust the printing pressure

5. Seepage occurs when printing materials are stacked. Main reasons: ① the curing speed of the material itself in the frosting ink is not enough; ② There is moisture or other solvents on the substrate; ③ Curing time is too short

solution: select the photo solid resin with fast curing speed, or appropriately increase the dosage of photoinitiator or photosensitizer, appropriately extend the curing time, and keep the substrate dry and clean

6. The printed matter has moire. Main reasons: ① the curing time is too long; ② The toughness of resin in frosted ink is not good; ③ Improper stretching method

solution: too long curing time will lead to excessive curing and post curing, resulting in cracking. Therefore, it is necessary to control the curing time, and choose the photo curing resin and active monomer with good flexibility to improve the moire phenomenon. Using oblique stretching instead of normal stretching can also avoid moire

7. poor adhesion of printed matter. Main reasons: ① due to the inevitable volume shrinkage of the photo solid resin and active monomer after UV curing, it is bound to affect the adhesion of the frosted ink on the low surface energy, non-polar substrate; ② There are impurities such as silicone oil, dusting, dust, etc. on the surface of the substrate

solution: for substrates with low surface energy and non signal polarity, such as PE, PP, pet, etc., corona treatment or other chemical and physical treatment should be carried out in advance before commissioning and use, while keeping the printing substrate clean

8. the toughness of printed matter is poor. It is mainly reflected in the post folding and cutting processes, which requires that the metering and mixing system equipped should be easy to crack within a suitable flow range. The main reasons are: ① the toughness of frosting ink itself is poor; ② The thickness of the ink layer of the printed matte ink is too large

solution, therefore, this material can also be used as a convenient electron emission source method: selecting photosolid resins and active monomers with better toughness, and appropriately selecting wires with higher mesh number to print thinner patterns can improve toughness

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