1. The main cause of blocking
1. The ink is dry on the layout
The ink remaining in the cell will be partially solidified due to some factors (such as increased ink viscosity). When the plate cylinder enters the ink tank again, the cured ink in the cell will be difficult to dissolve completely, and the ink will transfer The rate will decrease accordingly. Over time, the mesh holes are getting shallower and shallower, the ink transfer rate is getting lower and lower, and finally a blocking failure occurs. Such blockage failures are related to ink type, viscosity, solvent, drying speed, printing speed and other factors, and also have a great relationship with the structure of the printing machine.
2. Impurities mixed in the ink
The gravure printing speed is relatively fast, and the printing substrate (film) often generates static electricity during high-speed operation. Due to the adsorption of static electricity, dust and other impurities that fall off the printing substrate in the surrounding environment will be brought into the ink. These mechanical impurities are the direct causes of clogging of the printing plate mesh. In order to prevent such accidents, you can install an 80 to 120 mesh metal mesh in front of the suction nozzle of the circulation pump to filter the ink to remove insoluble impurities.
3. Low platemaking quality
Gravure plate-making has to go through multiple processes such as surface corrosion or engraving, aluminizing, and grinding. In these processes, the unevenness of the inner wall of the mesh due to corrosion or engraving, the burrs generated during grinding, and the Ω-type mesh, etc., all have a certain effect on the transfer rate of the ink. This leads to a reduction in the ink transfer rate, which can cause blockage.
4. Poor ink dissolution (deterioration)
Poor ink dissolution due to poor ink flow, turbid precipitation, or mixing of different inks due to incomplete cleaning after parking, and misuse of other poor solvents, and reduced transfer rates can also cause plate jams.
5. Chemical changes in ink
With the continuation of the printing process, two-liquid inks or reactive inks will gradually undergo crosslinking and other chemical reactions, which will deteriorate the ink fluidity, increase the viscosity, and reduce the transfer rate. These may be the reasons for blocking. Therefore, when using two-liquid inks or reactive inks, wipe the plates in time after shutdown, and use expired inks and residual inks with caution. In addition, the mixed use of different types of inks may cause chemical reactions, resulting in blockage. Therefore, experiments should be conducted in advance to confirm whether different types of inks can be mixed.
Second, countermeasures for blocking jams
1. When the fault of plastic gravure blockage occurs, it should be cleaned with a solvent or a special cleaning agent, and the causes of blockage should be resolved separately.
2. The temperature and humidity of the printing workshop should be suitable, and the drying speed of the solvent must be compatible with the printing speed and printing environment.
3. The distance between the squeegee and the impression cylinder should be as short as possible to prevent the hot air leaking from the drying box from blowing directly on the layout.
4. Mix slow-drying solvents to increase printing speed appropriately.
5. In case of blockage failure caused by ink performance defects, the ink should be replaced in time (or contacted with the ink supplier to solve it), and try to avoid the combination of inks with significant differences in specific gravity.
6. The ink in the ink tank should be stirred frequently to keep the ink in all parts flowing. New ink should also be added or replaced in time to avoid ink film.
7. When there is a blockage caused by the quality problem of the inner wall of the printing plate network, the plate should be re-plated or re-made.
8. Before or immediately after starting up, wipe the plate cylinder with solvent. During the printing process, it is necessary to avoid stopping halfway. If you stop for a long time, you must first clean the printing plate, or immerse the printing plate cylinder in the ink tank and continue idling.
9. In fresh ink, due to temperature differences, additives, waxes, etc. in the ink will crystallize out. At this time, you can try to warm the ink (40 ~ 50 ℃) before use to dissolve it.
10. Misuse of solvents, deterioration of ink, and mixing of different inks, etc., will significantly affect the resolubility of the ink. Therefore, regular special dilution solvents should be used. When replacing the ink, first clean the ink tank and circulation pump thoroughly, and then pour in new ink.
Children's Study Desk and chair set is furniture for children aged 3-18 to learn and write homework. The table has a lot of storage space. The platen is made of solid wood core material. The table board is adjustable, and the table legs can be raised and lowered to meet various needs. A tall child can do homework and draw; the Study Chair is an ergonomic chair that can be adjusted to protect the child's spine. The seat cushion is made of latex, which is very comfortable and will not be tired, so that children can learn healthily and happily.study table and chair, the height of the table and chair can be adjusted according to the height of the child. In addition to the most basic "cushion height" that can be adjusted, the "armrest and back cushions" can also be adjusted according to the child's thigh length and waist height. Adjust so that the child does not sit in the wrong position due to the improper height of the table and chair. And the chair is designed according to children's ergonomics, unlike ordinary chairs that are straight up and down, there is a double-back curve design, which supports the child's back and ensures that the waist and hips fit perfectly with the chair.
Aiguole children's study desk primary school desk can lift the table solid wood writing desk home desk and chair set can help children correct their sitting posture, prevent myopia, and protect the spine!
Study Desk Chair Set,Computer Table For Kids,Kids Art Desk,Modern Kids Table Chair
Igrow Technology Co.,LTD , https://www.igrowdesks.com