Application of the most popular gearless flexograp

2022-10-01
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The application of gearless flexographic printing machine in packaging

with the wider application range of domestic flexographic printing technology and the increasingly mature technology, flexographic printing related machinery and equipment and supporting materials have also initially formed a series. Flexographic printing is moving from traditional ordinary label products to high-end packaging and 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. Let's take a look at a case of choosing a flexographic press, from which we can draw some useful enlightenment

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, which requires six cans in a group, environmentally friendly printing, and portable. There are two kinds of packaging materials, one is carton, with 0.54mm thick (about 500g) kraft cardboard; The other is about 30U heat shrinkable film, which can be used with the filling line. This requirement of customers makes leshine

carton company have 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

varyflex670 has a maximum printing format of 670x880, which basically meets the requirements of medium width packaging. The machine abandons the traditional long shaft transmission. The whole machine adopts gearless transmission, that is, the printing plate cylinder and the embossing cylinder are driven by independent motors, avoiding some restrictions caused by gear transmission. It can print thick cardboard and film on the same equipment in 2015 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 200 m/min, the line die cutting produces nearly 15000 finished cartons per hour, and its production efficiency is no less than that of a gravure press. Take the average diameter of the smallest one of the three places to calculate the cross-sectional area for the drying of 30U heat shrinkable film during 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 dry the material, which will not produce the pumping deformation of the film caused by heating, Avoid affecting the registration between color decks. When drying ink on the large field, Shandong Huayu is an enterprise specializing in the production of aluminum alloy materials, which is controlled by Chinalco. It will not change the internal structure of materials 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. The registration Electrical Department of each color group determines whether the displacement control accuracy of the actuator is suitable to be integrated into the drive motor according to the calculated displacement. The scanning head can directly feed the registration signal back to the plate cylinder classics. Compared with the traditional servo motor registration mode, this design not only greatly improves the registration accuracy, And the 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. It basically achieves the effect of offset printing and reduces the waste of materials

in order to perfect the existing high light and dark tone level, varyflex670 first pays attention to the stability of the machine under high tension and high-speed operation. The wall plate of the whole machine is made of 3cm thick nickel steel plate, and the wall plate of the die-cutting area is thickened to 5cm, so as to avoid the loss of dark tone paste or dots 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 axial movement of the plate cylinder, Long flat needle roller bearings are beneficial to prevent 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 former magnetic knife can only die cut thin paper, 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. When printing thick cardboard, the waste leftovers 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 is not lower than 170 M/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 flexibly exchange stations, so as to develop some unique printing processes. Cold and hot stamping, wire bonding and other processes 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 does 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 degree automatic pre nesting technology can automatically find the initial position of the printing plate before starting the machine, so as to achieve preliminary registration. After starting the machine, it only needs the length of one paper path to complete registration, which will reduce the waste generated by inaccurate nesting and machine debugging, and improve the yield. The use of gearless transmission also overcomes the limitation of gear pitch, realizes the infinite change of printing repetition length, and makes the layout of products with different sizes more flexible when making plates

because of the selection of varyflex670 flexographic press, leshzaie carton entered a new market. 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

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