Before the gravure press is officially
started for printing, the gravure press should be adjusted accordingly
according to the printing process requirements of each product, and a series of
printing parameters matching the printing process requirements of the product
should be set on the press. Printers in China will mainly considerations
are as follows:
1. Drying temperature setting
Before starting printing, the drying
temperature of each unit should be adjusted according to the type of printing
material, printing speed, graphic area, ink layer thickness, etc. In the
process of high-speed printing, in order to make the solvent in the ink
volatilize quickly after printing and achieve the purpose of timely drying, the
setting of drying temperature is very important. Drying temperature has a great
impact on the quality of products, too high temperature will cause film
shrinkage deformation; too low temperature will not dry completely, causing ink
anti adhesion. In actual production, such as PVC film, the drying temperature
is generally 40 ~ 55 �, while OPP film can be dried at 60 ~ 75 �.
In the actual production, the setting of drying temperature can be based
on the influencing factors, usually printers in China will according to
the printing speed, the overall ink amount of the product, whether there is
metal ink, the thermal shrinkage characteristics of the film itself, etc.
2. Tension
General gravure press unit has four tension
control, respectively: unwinding tension, feed tension, traction tension, winding
tension. The more stable the tension is, the more stable the substrate will be
in the operation between the units, and the more guaranteed the accuracy of
color registration.
Film printing tension control is more
important than paper. The size of the tension adjustment is determined
according to the type and tensile strength of the film. For example, the
tensile strength of CPP and PE is weak, and the film is easy to be deformed.
Therefore, the tension should be correspondingly smaller, while the tension of
PVC, BOPP and other films with strong tensile strength can be correspondingly
larger. In the case of a certain type of film, the width and thickness of the
film are also important factors to determine the tension. The tension of wide
film should be greater than that of narrow film, and that of thick film is
greater than that of thin film.
3. Pressure between impression cylinder and
plate cylinder
Set the appropriate pressure according to
the thickness of the substrate. Generally, the greater the thickness is, the
greater the printing pressure is required.
4. Plate cylinder circumference and
impression cylinder diameter
Set the appropriate pressure according to
the printing process sheet. Generally, the greater the thickness is, the
greater the printing pressure is required.
5. Setting the change curve of winding
tension
In the printing process, the winding
tension decreases with the increase of the winding diameter. In order to obtain
better winding quality, the winding tension curve of the current advanced
gravure press can be set by the operator. Therefore, it is very important to
set a suitable winding tension curve for printers in China. In general,
several commonly used curves can be stored in the host, which is convenient for
production.
6. The position of the balance roll of each
color group returns to zero
The balance roll of each color group is
designed to adjust the non parallel pattern between plates. In general, the
balance roll should be kept parallel with each guide roll to prevent the
pattern registration from being affected due to the non parallel.
The setting principle of gravure press
parameters for every printers in China, is simple and effective.
