1. Hardness test with pencil
The technical conditions for the use of UV ink include pencil hardness. According to this requirement, we can use a pencil hardness tester to test. If the requirements are met (generally 3-4h), it will prove that the ink has been completely cured.
2. Test by dropping solvent
As mentioned above, there are also solvent resistant items in the technical conditions of UV ink, because after the ink is completely cured, the internal molecular structure will change, and the conversion to double bond will be complete when the conversion is high curing, and then the ink will form a solid coating as a whole. According to the solvent resistance, drop propionic acid solution on the board for 2min. If there is no change, it proves that the ink has been completely cured after being irradiated by the UV lamp.
3. Pressure test
This method is derived from the coating detection method. Select a 500g weight with flat bottom, place a few silk cotton fibers on the UV cured surface, press the weight on the cotton fiber for 2-3 min, and then remove the weight. If the cotton fiber does not stick to the surface, it proves that the surface is completely cured.
4. Appearance observation method
Completely cured uv ink has a bright surface, and there is no fuzz, no ghost on the edge, which is also one of the important characteristics to determine that the ink is completely cured by uv light.