Application of the most popular gearless flexograp

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The application of gearless flexographic printing machine in packaging printing

with the wider application range of domestic flexographic printing technology and the increasingly mature technology, a series of machines and equipment related to flexographic printing and supporting materials have also initially formed. Flexographic printing is moving from traditional ordinary label products to high-end packaging printing market. At present, some domestic cigarette bag printing and folding carton printing enterprises also pay attention to the application of flexographic printing in packaging printing, hoping to use new equipment, develop new processes and products, and keep up with the development trend of international packaging printing. The following will introduce a case of flexographic machine selection, hoping that readers can draw some useful enlightenment from it

Leshine carton company, located in Connecticut in the northeast of the United States, is a large printing enterprise that provides packaging for beverage and food companies, including offset printing and gravure printing. In 2002, packaging users asked them to provide packaging for cans of beer, requiring six cans in a group, environmentally friendly printing, portable. There are two kinds of packaging materials, one is carton, with 0.54mm thick (about 500g) kraft cardboard; The other is 30 μ The heat shrinkable film with a thickness of about M can be matched with the filling line. This requirement of the customer prompted leshinecarton to develop new processes. Finally, they chose the flexographic printing method to meet the new needs of the market, and introduced the varyflex670 unit type 8-color gearless flexographic machine of Italian Omet company to print thick cardboard and film products

the maximum printing format of varyflex670 is 670mm × 880mm, which basically meets the requirements of medium width packaging. The machine abandons the traditional long shaft transmission mode, and the whole machine adopts gearless transmission for future reference, that is, the plate cylinder and embossing cylinder are driven by independent motors. Some restrictions caused by gear transmission are avoided, and thick cardboard and film can be printed on the same equipment without replacing any components

for thick cardboard printing, varyflex670 adopts non-stop unwinding with a unwinding diameter of 1500mm in the unwinding part. With a printing speed of up to 200m/min, the line die-cutting produces finished products every hour, and the load can no longer increase by nearly 15000 cartons. Its production efficiency is no less than that of a gravure printing machine. For the drying of heat shrinkable film printing, with the cooperation of the research and Development Department of Omet, each printing unit of varyflex670 adopts a large 24 inch water-cooled roller, the printing material is wrapped on the water-cooled roller with circulating cold water, and the hot air and UV drying device are mounted on the water-cooled roller to realize the strong cooperation in the field of material experiment to dry the material. This way will not produce the swelling deformation of the film caused by heating and avoid affecting the registration between color groups. When drying ink on the large field, increasing the hot air power will not change the internal structure of the material and avoid accidents such as fire

in terms of tension control, in order to adapt to a wider printing range, the operator can call different tension control curves to match different materials before starting the machine, and the tension value will be automatically adjusted to the preset range before starting the machine. The tension control mode of three levels and four sections is adopted, and the multi tension floating roller with high sensitivity is used, which can control the tension of unwinding, printing, die cutting and winding separately without affecting each other. The paper pressing roller driven by an independent motor is very sensitive to tension and can rotate forward and backward. The unique tension control system provides a good prerequisite for registration

varyflex670's registration system is very unique, because it adopts the gearless transmission mode, and the registration electrical part of each color group is integrated into the drive motor. The scanning head can directly feed back the registration signal to the plate cylinder motor. Compared with the traditional servo motor registration mode, this design not only greatly improves the registration accuracy, but also registration is very fast. Customers even print 10 colors with 8-color equipment (roll to roll 8 colors first, then print 2 colors plus light) without changing the overprint accuracy, which basically achieves the effect of offset printing and reduces the waste of materials

in order to perfectly reproduce the highlights and dark levels, varyflex670 first focuses on the machine in high tension. For stability under high-speed operation, the wall plate of the whole machine is made of 3cm thick nickel steel plate, and the wall plate in the die-cutting area is thickened to 5cm, so as to avoid the phenomenon of dark paste or dot loss caused by machine vibration. The double bearing structure is adopted on the plate cylinder. During the high-speed operation of the machine, the ball bearing is conducive to preventing the plate cylinder from axial movement, and the long flat needle roller bearing is conducive to preventing radial runout

in the die cutting unit, varyflex670 adopts dual magnetic roller technology. The steel knife cover with Yin-Yang matching sleeve overcomes the shortcoming that the magnetic knife can only die cut thin paper in the past, extends the service life of the die-cutting knife cover, reduces the service time of the die-cutting knife, and shortens the processing delivery time from twoorthree months to one week. The waste scraps produced during printing thick cardboard are first chopped in the die-cutting unit, and then sent to the waste paper warehouse by a conveyor belt. The machine printing processing speed shall not be less than 170m/min when connecting the die-cutting thick cardboard

considering the scalability of the machine, varyflex670 can draw out the ink supply system of various color groups along the guide rail, install roller wire printing unit and rotary gravure unit at the corresponding position, and can flexibly exchange work, but the low-cost single-purpose tensile testing machine with electromechanical as the power source is widely used, which is commonly known as electric drawing, so as to develop some unique printing processes. Cold, hot stamping, wire bonding and other units can also be conveniently installed at any position. On the platform of flexographic printing, the combination of multiple printing processes is truly realized

on the operation interface, varyflex670 minimizes the influence of the operator on the production, and uses the European patented half cam pressure control technology. The adjustment of printing pressure and ink supply pressure can be independent of each other and do not depend on the experience of the operator. The use of sleeve technology not only reduces the labor intensity of operators, but also reduces the cost of replacing sleeves of different sizes. 360 ° automatic pre nesting technology can automatically find the initial position of the printing plate before starting up, so as to achieve preliminary registration. After starting up, it only needs the length of one paper path to complete registration, which will reduce the waste caused by inaccurate nesting and machine debugging, and improve the yield. The use of gearless transmission also overcomes the limitation of gear pitch, realizes the stepless change of printing repetition length, and makes the layout of products with different sizes more flexible when making plates

leshinecarton entered a new market because of the selection of varyflex670 flexographic press. In terms of printing quality, Mr. August, its production manager, said, "when we use UV ink, many technical indicators have exceeded offset and gravure printing." Mark, its marketing manager, said, "after the installation of varyflex670, our market competitiveness has been enhanced. We can print materials from extremely thin to ultra thick, and improve the satisfaction of packaging users. We can flexibly configure on the basis of the existing flexo production line, and the market is broader."

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