Main reasons: uv power is not enough; Uv lamp aging, strength weakening; Improper selection of UV varnish initiator; Alcohol, toluene and other solvents added too much; Machine paper speed is too fast; UV varnish has poor photosolid properties.

Solution: timely maintenance of equipment and replacement of lamp; Adding a certain amount of photoinitiator and photosensitizer, such as ternary amine, to speed up the speed of the skin; Adjust printing process.