Misregister is common
issue in flexo printing process. This passage summarizes some causes and
solutions for readers’ reference.
1 Printing tension
setting problem
The printing
tension directly affects the overprinting accuracy of film materials. If the
tension is too small, the material will loosen, and overprint errors will
occur. On the contrary, if the film material is stretched and deformed, it will
also affect the overprinting accuracy. Therefore, when printing film-like
self-adhesive materials, the printing tension should be set to the minimum
value to ensure the accuracy of overprinting.
2 UV lamp temperature is too high
Thin film materials are significantly affected
by temperature. If the temperature of the UV lamp is too high during printing,
it will deform the film material and affect the overprinting accuracy. At this
time, the power of the UV lamp can be reduced to reduce its temperature.
However, in actual production, it is often contradictory. The power of the UV
lamp is high, the material is deformed, and the overprint is not accurate.
However, the power of the UV lamp is reduced, and the overprint is accurate,
but the ink is not easy to dry. Therefore, it is necessary to solve the problem
comprehensively, such as priming ink, selecting ink suitable for the material,
or changing the printing color sequence, printing ink that is not easy to dry
first, etc.
3 Bad slitting effect of material
The end surface of the material is uneven,
and there will be overprint movement during printing. If the material is wide,
it can be slit twice. Both sides can be slit off by 2mm. If the material is not
wide, the material can only be replaced.
4 Inconsistent material tension
Film-like materials are very sensitive to
tension. If the tension at both ends of the material is inconsistent, it is
easy to deviate during printing and cause misregistration. Usually, if one side
of the material is flat and the other side is tight, ruffles will appear. At
this time, it is recommended to use a paper printing machine with deviation
correction equipment to reduce misregistration.
5 Material thickness error
There is a deviation in the amount of glue
applied to the self-adhesive material. Sometimes the amount of glue coated has
a large deviation, which will cause thickness errors at both ends of the
material, causing printing deviation and affecting the overprinting accuracy.
At this time, the material needs to be replaced or the material should be
reduced for use.
