First, the main factors affecting the quality of gravure printing products 1. The change of ink performance requirements for ink:
1 ink should have appropriate thixotropy and good fluidity;
2 to have a good drying capacity and adhesion;
3 to have enough cohesion to prevent the centrifugal force imbalance when the copper plate is running at high speed;
4 To have an adapted re-solubility, the ink in the dots cannot be completely transferred to the material during printing, and some parts remain in the dots. If there is no proper re-solubility, it may cause blocking.
2, changes in tension:
1 If the tension is too small, the film is loose, affecting the overlay accuracy;
2 if the tension is too large, the film wrinkles, stretch deformation, adhesion, etc.;
3 Thick film tension is greater than thin film.
Second, the factors that affect the drying speed of gravure printing ink 1. The influence of solvent;
(1) The role of solvents;
1 diluted ink;
2 dissolve, uniform ink;
3 to drive the ink, determine the viscosity of the ink;
4 improve the ink printability, such as anti-static and so on.
(2) The volatilization rate of the solvent should be measured by the boiling point. The lower the boiling point, the faster the evaporation rate. Conversely, the higher the boiling point, the slower the evaporation rate.
2, the impact of drying device:
Usually, OPP begins to soften at 88°C. Therefore, the oven temperature should not exceed 85°C. Generally, the oven temperature can completely dry the ink (45 to 60°C). If the temperature is too high, the residual heat remaining in the film after printing will cause anti-adhesion, especially gold.
3. The influence of the printing plate level:
(l) The outlet is too deep: it is mainly caused by the deep etching of the printing plate. Solution; Add dilute agent, reduce ink color concentration, increase the scraping angle. Increase the pressure of the squeegee, ink layer thickness, ink drying is difficult, and re-plate.
(2) The outlet is too shallow: the corrosion is too shallow. Remedy; Use dark ink to reduce the pressure of the squeegee. Reduce the squeegee's squeegee angle.
4. Influence of ambient temperature: The higher the temperature, the faster the drying.
Third, the technical measures of printed gravure products 1, the amount of ink control: the amount of ink to be determined according to the depth of the printing plate network, deep ink network cable with a large amount of ink, less ink.
2, color printing.
3, "sticky bottom." After printing the rolled product, the ink layer adheres to other contact surfaces, making it impossible to unwind.
(1) The remaining (residual) solvent is not completely evaporated. The resulting ink softens anti-sticking. Solution: Store the product in a cool place and reduce the printing speed.
(2) The printing temperature is too high or the humidity is too high. Solution: Reduce the ambient temperature as much as possible and keep it dry.
(3) The winding tension is too large, or the ink area is too thick at the same position. Causes increased local tension.
(4) The printing area is too thick. Solution: The depth of the network is controlled at 25 ~ 28μm, too deep, anti-sticking, and printing is difficult to control.
Gravure product quality control
December 16 04:07:54, 2023
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