China White Birch UV plywood Part 9 : UV plywood Manufacturing Defects
Problems and Countermeasures
Reasons: a. The ink crystallized. B. The surface tension is high and the wetting effect of ink layer is not good.
Solution: a. Add 5% lactic acid to UV oil, destroy Changhua film, remove oil or wool treatment. B. Reduce the surface tension value and add surfactants or solvents with lower surface tension value.
Stripe and wrinkle
Reasons: UV oil is too thick, coating amount is too large, mainly in roll coating.
Solution: Reduce the viscosity value of UV oil, add appropriate alcohol solvent to dilute.
Reasons: a. UV oil has high viscosity and poor leveling. B. Coating rollers are too thick, not smooth and the amount of coating is too large. C. The pressure is not uniform.
Solution: a. Reduce viscosity, import leveling agent and appropriate solvents. B. Select fine coating rollers and reduce the amount of coating. C. Adjust pressure.
Reasons: a. Insufficient ultraviolet light intensity or too fast machine speed. B. The storage time of UV light oil is too long. C. Excessive addition of diluents not involved in the reaction. Solution: a. When the curing speed is less than 0.5 seconds, the ultraviolet power should not be less than 120w/cm. B. Adding a certain amount of UV light oil curing accelerator or or replacing light oil. C. Pay attention to the rational use of diluents.
Not painted or blossomed
Reasons: a. The surface of printing ink produces crystallized oil, powder spraying and so on. B, ink and ink oil and too much dry oil. C. too low viscosity of UV varnish or too thin coating. D. Glue-coated mesh rollers are too thin. E. The conditions of photo-curing are not suitable. F, UV varnish itself has poor adhesion and printing materials have poor adhesion.
Solution: a. Eliminate crystallization layer, wool treatment, remove grease or add 5% lactic acid. B. Select ink accessories matching with UV oil process parameters or wipe them with cloth. C. Use UV varnish with high viscosity to increase the amount of coating. D. Replace the reticulated rollers matching the UV gloss oil. E. Check whether the ultraviolet lamp tube is aging or the machine speed is not consistent, and choose the appropriate drying conditions. F, top and bottom glue or special UV varnish or select good surface properties.