Prevention of three printing faults
fault one shrinkage
the ink film on the surface of the product after printing retracts, exposing the surface of the substrate in a larger area of the printing surface. This phenomenon is called shrinkage. This is due to poor wetting of the printing ink on the substrate. For example, the substrate surface contains oil stain, plastic surface and electrodeposition printing with too many surface scratch prevention additives 9 Effective elasticity and hysteresis loss: brush the ink surface on the leather tensile testing machine, so that the printing plate is not centered or eccentric, and it is difficult to deal with the forward direction. It is difficult to shrink (there is no longitudinal), often resulting in partial shrinkage (fracture)
preventive measures: strictly degrease the surface of the substrate before printing, and select special printing ink with low surface tension
fault two pockmarks and pits
because the wet ink film of the printing ink is stained with foreign particles, these foreign particles spread on the wet ink film and repel the surrounding ink to form pits, also known as pits. It is obvious that there are foreign particles in the center of the pit of the horizontal tensile testing machine, also known as pockmarks. This phenomenon generally does not reveal the substrate
preventive measures: control the environment, improve the cleanliness, and ensure the purity of the solvent or diluent without foreign matters
fault three thick edges
the ink film is particularly thick at the corners after printing, and the finished product looks like a mirror frame, which is called thick edges. This is because the solvent volatilization of the wet ink film on the corner is faster than that of other positions, causing the ink concentration at this place to be too high and the temperature to be lower than that elsewhere, forming a high surface tension area, making the adjacent ink flow to the corner, thickening the ink film at this place
preventive measures: improve the thixotropy of printing ink, reduce printing pressure, or add an appropriate amount of rheological additives
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