Guidance on the correct use of visual positioning machines and machine-sprayed coatings in the emblem industry.
First, the thickness of the coating film has a great impact the adhesion of UV printing.
1. The thickness of the screen printed coating is most affected by the temperature among the parameters of the nozzle. Since the viscosity of the coating is extremely high at room temperature, it will affect the spraying force of the nozzle. The optimal operating temperature for screen printing is 45℃, which allows the viscosity of the coating to drop drastically, thus ensuring the efficiency of ink ejection from the nozzle. The tension of the coating will also be reduced, which is also helpful for adhesion. Therefore, the secondary ink cartridge should be heated, at least to maintain around 40℃, and the nozzle temperature should be kept at 42-45℃.
2. Regular maintenance of the nozzle also has a significant impact on the nozzle condition.
The screen printed coating has adhesion to the nozzle panel. If the surface is not cleaned when wiping the nozzle, and with the reflection of UV light, once the coating is cured, the nozzle is very likely to be blocked.
In the badge industry, since the patterns printed are very small, the nozzle is in a state of intermittent small inkjet for a long time, so the nozzle is prone to clogging, and it is also exposed to backlight for a long time, so it is prone to blockage. When we visited the enterprises, we found that the operators only wiped the nozzle twice with a dust-free cloth when wiping the nozzle, which actually cannot clean the coating on the nozzle. The correct way is to use a special cleaning solution with a dust-free cloth to wipe it multiple times until the surface of the nozzle is completely clean (at least wipe it with a dust-free cloth with cleaning solution more than 6 times). At the same time, the nozzle should be deep cleaned regularly to prevent the residual coating from solidifying on the surface of the nozzle, causing the nozzle hole to be blocked or the ink ejection to be unsmooth. In addition, operators should develop good maintenance habits, clean the nozzle in time after each use, and check whether the nozzle temperature is maintained within a suitable range to ensure the long-term stable operation of the equipment. Through scientific nozzle maintenance methods, the service life of the nozzle can be effectively extended, and the quality and efficiency of UV printing can be improved.
Second, the very critical factor that affects the instability of badge adhesion is the oil contamination on the surface of the badge.
The badge had a greasy feel to it at the time, but there was nothing visible to the naked eye. When burned with a, there were white spots all over, which were oil stains. Because the badge goes through many processes before printing and there is no protection, this situation requires cleaning with an alcohol-aked lint-free cloth and then printing again. After washing and printing again, the adhesion immediately went up.
If alcohol cleaning is also ineffective, you can use strongvents such as toluene for cleaning. If that still doesn't work, there is only one solution, which is to have the gold ink manufacturer adjust the formula of the ink. Because the gold ink on the surface of the badge requires high gloss and hardness, there are many leveling agents added to the formula. Most of these leveling agents are silicones, which can affect recoating, thus the coating has no adhesion. The solution is to make it clear to the gold ink manufacturer that when adding leveling, add leveling agents that do not affect recoating. This is also the main reason why many badges cannot be printed with UV printing. Because UV printing has higher requirements for surface tension of the material, if there is oil or improper treatment on the surface, it will cause the ink to fail to adhere. Therefore, for similar problems, the first step to confirm whether it is surface contamination, and then to process it through appropriate cleaning methods. If the problem still exists, it is necessary to communicate with the supplier to adjust the to ensure the effect of subsequent printing.
Third, in order to ensure the stability of the badge color printing adhesion, the company should establish its own quality control system.
It is precisely because the adhesion of this industry is difficult to guarantee that the printing manufacturers themselves need to have a bottom line, to establish own quality control, and not just print, but also check how the adhesion is. The specific points are as follows:
1. Before printing, ensure that the nozzle can guarantee the thickness of the coating.
2. Check whether the material needs to be cleaned.
3. The printed workpiece needs to undergo a hundred-grid test. the hundred-grid effect is very poor, there will be risks. Because UV ink is limited by its own physical properties, if it encounters humid, soaked, low temperature and other, it will become worse, and some will peel off and produce bubbles and other phenomena. If the requirements are high, in addition to the conventional hundred-grid test, it is necessary to increase the wet and heat aging test and low temperature impact test to comprehensively assess the ink coating under different environments. The performance effect cannot be judged simply by scratching with a.
4. For the customer's material, different manufacturers, different products, and even different batches (because of the fear of oil contamination, the formula of gold oil has) all need to do sample tests and confirm before producing large quantities.