Advantages of the most popular sheet fed gravure p

2022-08-11
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Analysis of the advantages and practical examples of sheet fed gravure printing machine

in the early 1970s, after careful analysis of itself and comprehensive research on the printing and packaging market, Moog company believed that the gravure printing machine will continue to flourish in the packaging and printing market for a long time, and the sheet fed gravure printing machine has a better development prospect than the web gravure printing machine! In 1996, German moger company sold its first three-color sheet fed gravure printing machine in China in Chongqing through its general agent in China at that time, Baolong foreign firm, and then sold several more in Hubei, Guangdong and other places. Since the end of 1999, MOG's sales in China have shown a momentum of rapid growth

against this background, China is enjoying a climax of producing and purchasing sheet fed gravure printing machines. At present, there are many single concave machine manufacturers in China, such as Beijing zhenhengli Printing Machinery Co., Ltd., Shanghai Ziming Machinery Co., Ltd., Shanghai Hairun Printing Machinery Co., Ltd., the third printing machinery branch of Shanghai Electric Group Printing and Packaging Machinery Co., Ltd., and beiren group. At present, the number of domestic single concave machines has exceeded 200

why is the single concave machine so popular? What obvious advantages does it have? How about the use of domestic single concave machine, and how do domestic users give full play to the advantages of single concave machine to make it worthwhile? In this regard, we interviewed several professionals

I. advantages of single gravure press

it is reported that compared with web gravure press, single sheet gravure press is very suitable for medium and small batches of high-quality prints, and its advantages mainly lie in:

1 Flexible printing operation, short preparation time and product conversion time

2. Overprint accurately. Its overprint accuracy is exactly the same as that of the sheet fed offset press

3. It's better to use less oil according to the requirements of the specification. Under normal circumstances, after the printing starts, the first oneortwo prints can be printed normally after adjustment, and almost no waste products will be produced. And web gravure printing machine, in high-speed operation, once there is printing color problem or registration problem due to tension, the waste of paper is often up to dozens of meters or even hundreds of meters. Greatly increased the printing cost

4. Flexible equipment configuration. Usually when buying web gravure printing machine, you must buy five color, six color or even seven color machine, so as to be in place in one step. This is bound to greatly increase the amount of investment. The sheet fed gravure printing machine is very flexible. You can buy five color, six color and other multi-color machines at one time, and you can also choose three color, two color and even monochrome machines

5. There is no need to spray powder, and there is no ink accumulation and ink color fluctuation

6. Printing materials that are difficult to print by offset printing machine, such as vacuum aluminized paper (gold card paper, silver card paper), metal foil, etc

7. It can print gold, silver, imitation metal etching and printing fluorescent ink, covering white ink, pearlescent ink, UV varnish, water-based varnish, etc

8. Inks and varnishes dry quickly and can be processed immediately, such as cutting, embossing, die cutting, etc

9. Printing ink can almost always achieve the desired thickness, and its one-time transfer of pigments is 4 times more than offset printing

10. It can print 0.03 (80g/m2) - 0.04mm thick cardboard

11. When printing large-area color blocks, there will be no ink lightening and "ghost" faults

12. The ink color is stable and consistent

13. The printing resistance can reach several million prints

14. The printing machine has simple structure and does not need ink transfer rollers and ink bucket screws

to sum up, it can be said that sheet fed gravure printing is a printing method that integrates many advantages, which is no wonder that the domestic packaging and printing industry loves it. However, sheet fed gravure printing is not perfect, and it also has insurmountable defects, such as: it is inferior to offset printing in dot, layer and thin line printing; Expensive plate making, etc

in fact, in addition to four-color printing, many high-end packages often need to print spot colors and gold, silver or polish. For such packaging, if only offset printing is used, the effect of spot color and printing gold and silver will be greatly reduced. In this regard, people in the industry will combine offset printing and sheet fed gravure printing. The eye tone part will be printed on a large area of the field or with a single gravure machine that needs special effects, so as to truly achieve the purpose of low cost and high quality, thus benefiting the printing manufacturers infinitely

II. Application examples of single concave machine that should be constantly monitored in China

application example 1: Chuzhou newspaper printing plant

Chuzhou newspaper printing plant is the largest packaging and decoration printing plant in eastern Anhui Province and the designated printing unit of cigarette standards of Anhui tobacco company. The company has successively introduced 4 yaai single concave machines and 2 zma90 (yaai improved) single concave machines developed and produced by Shanghai Ziming Printing Machinery Co., Ltd. It is mainly used for large background ink printing, gold silver ink printing, pearlescent ink printing and glazing (including solvent based glazing and water-based glazing)

although the single concave machine is easy to operate, it is not used to print good products. In the production process, we must pay attention to the factors that affect its use and give full play to its maximum function under the optimal environmental conditions. In this regard, Mr. Wei He, deputy director of Chuzhou newspaper printing plant, has a deep understanding. He believes that the main factors affecting the quality of sheet fed gravure printing products are: environmental temperature and humidity, drying hot air temperature, control of blowing and exhaust air volume, printing plate quality, ink formula, printing machine speed, etc. The details are as follows:

1 When using the single concave machine, the environmental temperature and humidity must be controlled well. Too high temperature or too low humidity will accelerate the evaporation of solvent in the ink, resulting in dry plate phenomenon, broken pens and lines on the print, and white spots on the field; On the contrary, if the humidity is too high, the amount of water absorption in the ink will increase, which will also cause white spots or "water marks" on the printed products. Therefore, we must control the temperature and humidity of the sheet fed gravure printing workshop. In addition, the volatilization speed can also be controlled by adjusting the formula of the ink solvent, so that the problem can be solved

2. The technical index requirements of sheet fed gravure printing for paper are basically the same as other printing methods, but because the sheet fed gravure printing products need to be dried through the drying channel, the water content of the paper is required to be small, otherwise the paper is easy to stretch and deform after drying, affecting the overprint accuracy

3. Sheet fed gravure printing requires the fluidity of the ink, the menu prompt is good, and the pigment particles in the ink are fine; The color density of color ink should be high; The content of resin in ink additives (such as ink blending oil, gold blending oil, diluent, etc.) should be high to increase the adhesion of color ink; The smooth degree of varnish is good to ensure friction resistance

4. The diameter of the plate cylinder used by the single concave machine should be made in strict accordance with the size required by the original machine to minimize the error. The conical holes at both ends of the plate cylinder should be concentric (because the factory uses a single concave machine to pass through the shaft printing plate, and both ends are clamped with cone heads), and its cone surface should be consistent with the cone head on the shaft, otherwise there will be the fault of inaccurate overprint and inaccurate printing

5. The engraving method and technical parameters of the drum should also be different according to the different print layout (such as: field version, line version, gold printing version, silver printing version and glazing version). The specific parameters should be discussed jointly with gravure plate manufacturers according to different prints

application example 2: Guilin aoqun Color Printing Co., Ltd.

Guilin aoqun Color Printing Co., Ltd. is an important packaging and decoration enterprise in Guangxi Province. The zhenhenry sheet fed sheet fed intaglio printing machine introduced by it is only used for the printing of high-end cigarette packets

Mr. Li Yong of the company believes that the main factors affecting the use effect of the single concave machine are: the temperature and humidity in the production workshop, the radial runout of the drum, the uniformity of the biting force of the paper gripper, the angle of the scraper, the viscosity of the ink, the type and dosage of the solvent. He suggested:

1 When using the single concave machine, the ambient temperature and humidity must be controlled within a certain range. The temperature should be 23 ± 2 ℃, and the humidity should be maintained at 55% - 60%. If the temperature is too high, the solvent based ink used volatilizes too fast, and the viscosity of the ink changes significantly, which is reflected in the printing products, showing that the ink color is unstable. If the humidity changes too much, it is easy to cause the paper to stretch and deform, making the printing overprint inaccurate

2. Sheet fed gravure printing has clear technical requirements for printing raw and auxiliary materials, with a year-on-year increase of 35.8%. Among them, the ink and paper type must match. After use, it is found that the problem of ink is more prominent. Therefore, we must choose the appropriate ink and solvent, and ensure the same proportion

3. According to the characteristics of printing products, the gravure cylinder with corresponding accuracy is selected. For high-precision products, laser engraving intaglio should be selected, and the mesh number should be high, and the hole diameter and depth should be stable and consistent

4. When using single concave machine to produce sanding effect, we should choose sanding oil with good performance and adjust the temperature of heating lamp. According to the actual production needs, the single concave machine can be transformed to some extent, such as adding a powder spraying device

5. At present, the machining accuracy of domestic single concave machine is not very high, and the rule adjustment is not very convenient and accurate. The paper receiving and feeding device needs to be further improved

according to the above two examples, it is not difficult to see that during the printing process, the single concave machine still has certain special requirements for the ambient temperature and humidity, as well as the performance of paper, ink and glazing materials. Attention must be paid to ensure the smooth operation of the single concave machine and print products satisfactory to customers

in addition, in the investigation and interview, we also learned some weaknesses of domestic single concave machines, such as: domestic equipment can not catch up with imported equipment in terms of accuracy and mechanical stability; Some devices are prone to problems such as dryness due to their slow speed; The distance between the printing plate scraper line and the embossing line is large, and the printing plate is exposed to the air for a long time after being scraped, which affects the printing quality

in a word, the single concave machine is a new model in China, and its process requirements are quite different from that of the web gravure machine. In particular, the cooperation of equipment manufacturers, plate makers and ink factories is needed to improve the process level and give full play to the effectiveness of the single concave machine. It also requires equipment manufacturers to conduct in-depth research and produce single concave machines with faster speed and higher quality

source: keyin media

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