Gravure machine offline die cutting
Li Yulong
1. Reduced design
The gravure printing machine is not only suitable for plastic film packaging prints, but also suitable for the production of paper type prints. After the film type prints are printed and rolled, the post-synthetic bag making and cutting processes are reasonable and mature, and will not be discussed. Only The methods used in the post-processing of paper-type gravure printing products should express my own opinion. There are quite a few varieties of gravure printing products for packaging cartons, especially cigarette packs. We now take cigarette pack production as an example to compare the traditional production process with the off-line die-cutting process, analyze its advantages and disadvantages, and put forward viewpoints to discuss with the people in the industry.
The gravure printing machine is a production method that adopts the material feeding and non-stopping technology. After the color printing, it is taken into the form of a roll and taken off. After off-line, the roll-shaped printing product is cut off and collected by a single marking length and then collected. The single sheet of printed matter that is collected and cut off is subjected to spine prominence, indentation, die cutting, rejecting, collection, inspection, and packaging. If the printed matter is to be hot-stamped or laser-marked, the procedure needs to be increased. The disadvantages of the above process are many processes, large area, use of machines, and many personnel. Sometimes off-line operations of web printing interrupt the accuracy of the cross-cutting process, and a large number of inspection personnel and large-area work spaces are also required. Because the Zhang Zhang is to serve the next process, each print must be clipped (at least 15 mm) in length, which directly results in a reduction in paper utilization. For bronzing, indentation, and crosscutting, at least two more applications are required. Materials will be deformed due to changes in air temperature and humidity during the turnover of the shop, resulting in an increase in scrap rates. The above conditions are relatively clear to the industry. Since all factories use the same kind of technology, everyone is on the same starting line in competition, and there is no competitive pressure brought by new methods and high efficiency.
The traditional process flow will inevitably change with the development of industrial technology. The first is to change the traditional gravure winding method to continuous machine breaking, and the cost of the machine-breaking structure is low, and an offline crosscutting machine is eliminated. Because the tension and breaking tension are on the same tension section when the machine is broken, the accuracy of the cutting is also more accurate than the off-line breaking, so it is widely used in many gravure box production lines. After the bronzing and spine process, indentation and die-cutting process have to adopt the traditional way. In order to solve the existing problems, there are also a small number of imported machinery manufacturers adopting a machine for indentation, die-cutting, and collecting processes. Although technology has been implemented, there are many drawbacks. The analysis is as follows: The gravure printing machine is a high-speed non-stop machine. In the state of work, the traditional paper-splicing method is a method of fast splicing of the tape, and a double-layered printing material having a length of about tens of centimeters at the joint. In the gravure printing group, since the embossing roller is a rubber roller, although slight vibration can still pass, when it enters the indentation and die-cutting station, it will greatly impact the indentation on the roller and the die-cutting roller. Life is reduced. At the same time, due to the high-speed production of rejects and the collection of finished products, irregular joints will cause the collection table to fail. Once the paper collection table fails, it will cause the gravure printing line to stop. Therefore, when connecting to the gravure printing machine, the non-stop decoiling mechanism must be designed as a butt joint in order to ensure a good working condition. This will make the gravure winding mechanism bulky and increase the cost, because the docking paper is carried out at zero speed, it is bound to design the paper storage rack, joint strength and tension control is difficult, joint success rate is not very high, The system costs about 2 million yuan in imports from France.
There is also a technically troublesome problem. Before the gravure printing machine is turned on and in the gravure printing, a sudden stoppage occurs. If the process in printing is down, the gravure printing group must be pressure proofed for secondary printing. In the case where the material in the cross-cutting station must be kept from being fed between stations, a clutch must be used to separate the gravure from the post-processing section. The gravure printing station must also perform the pressure-compression operation after the dampening station is dampened and the memory is kept in the original phase after the second production is put into operation. Only after the gravure printing station is put in again, the printing and die-cutting positions are misaligned. The mechanism is complex, the operation is difficult, and the cost is high. At the same time, the accuracy of the position is affected due to the complexity of the system. We believe that the above method is not desirable, and in fact there is no successful use of examples. Some people may think that this concept is arbitrary and can be solved without a shaftless drive? Yes! If each printing unit and each post-processing unit use an AC servo shaftless transmission, there is no contradiction as explained above. Even if we do not talk about the high price of using this system, we must consider that the entire electrical system must be very reliable, because the system printing manufacturer can not be equipped with maintenance personnel. Even so, we analyze the value is not worth doing. Because the printing process requires speed, constant viscosity of the temperature ink, and non-stop production conditions, ink consistency can be guaranteed, high-quality prints can be obtained, and high yields can be achieved. When working in each color group, the operator is required to monitor the working condition of each color group in an honest manner to ensure that the failure cannot be caused by the shutdown. The subsequent processing steps are to perform bronzing (including cold stamping), spine, indentation, and die cutting on the printed screen, and to allow shutdown when performing the above operations. Downtime does not result in lower quality and increased scrap. According to the basic requirements of the printing operation and the post-processing operation, it is contradictory that the production of the two different types of processing operations is continuous. When the post-processing process is gilding, it is impossible to stop the film roll when the film roll is used up, and the film roll must be stopped. Once the finished product collection and waste rejection fails, the machine must be shut down for troubleshooting. If continuous machine production will inevitably affect the printing quality and yield, the waste can be imagined once the machine is shut down and restarted on a multi-color printing press.
Through the above analysis, we believe that the web prints printed on the gravure printing machine do not need to be broken, but rather the web is taken off-line and it is a sensible choice to connect the subsequent processes after processing. First of all, after unwinding the web, the print is pre-positioned through tension and position control. We can then reprint, reposition hot stamping (including cold lamination), and double-position the laser for hot stamping. The spine marks, creasing, and scrapping can be performed. The collection of finished products, continuous success, made us complete a revolutionary change in the subsequent process. This will reduce the number of printers in printing companies, save printed materials, reduce personnel, reduce the area of ​​the factory, increase the yield, reduce energy consumption, and in short, the advantages are many, and the prospects are very attractive. At the same time, industrial competition also forces us to make such a choice.
The reason for the above realization is very clear. The possibility is beyond doubt. This is equivalent to the fact that we originally had a cross-cutting machine for cutting off the sheet, but now we have expanded the function of the standard cross-cutting machine and increased the number of other stations. Integrated operations.
The general manager of Xi'an Black Bull Machinery Co., Ltd., after many years of exploration and practice of our company, we have developed an off-line gilding die-cutting machine by combining the on-line operation function of the flexo printing machine with the offline repositioning function. The company's domestic gravure printing machine (Dongyang, China, Golden Three Gorges, Hubei), which was developed by the company, has been used for more than one year. Its die-cutting accuracy has been well received by users and we have applied for patented technology. The customer (Xi'an Dafeng Printing) has been using for more than one year, and the laser marking and double-positioning of prints have been successfully tested in the company, including the transparent laser pattern UV drying positioning transfer technology.
I believe that with the gradual recognition of this technology among industry professionals, our sincere friend and friends in the gravure printing industry will continue to make technical exchanges and make common progress. This will make the traditional craftsmanship and the offline advancement process more advanced. Prove that our company stands at a higher starting point and participates in market competition.
Reprinted from: Guangdong Packaging - 2006 Issue 4
Specifications
2. Anti-slip velvet
3. High toughness carbon steel
4. PU chassis
5. PVC upper
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