Soft concave technology applied in the field of flexible packaging printing

Now, flexographic printing has received unprecedented attention in our country. In recent years, many flexographic printing equipments have been introduced. Many people in China think that flexo printing is a new process. In the future, there will be a wave of “plastic to soft, concave to soft”. However, on the other hand, these devices have not achieved the expected results (including product quality, productivity, and economic efficiency) compared with the original situation of introducing offset and gravure equipment. In order to make the healthy and rapid development of flexo printing in our country, we must solve some problems in the development of flexographic and gravure printing from the understanding and practice.

1. The trend of foreign backbone vendors A. Gravure and flexo are not new printing processes. Although flexo printing was really valued in China in recent years, it has experienced many years of development as gravure.
B. Manufacturers in the world are increasingly able to produce both devices simultaneously. There are two different situations in the development process of the more well-known manufacturers in the world: one is the original gravure printer manufacturer, and later the production capacity of flexo presses is increased through acquisition and holding; the other flexo printer manufacturer is later Increase the production of gravure printing machines. Companies such as Cerutti, Valmet, Rotomec and Bobst belong to the former category, and companies such as W&H and UTECO belong to the latter category.
C. From the point of view of the printing and processing manufacturers, many well-known foreign printing manufacturers have conducted research on these two technologies and made corresponding investments. Both of them have installed flexographic and gravure printing equipment to provide customers with various options.

2. Application areas and product directions The main application areas of gravure and flexographic printing are roughly the same, but not exactly the same. In the fields of packaging and trademark printing, publishing and printing, decorative printing (grain paper and transfer printing) and other special printing (such as banknotes, stamps, lottery and other securities), the advantages of gravure printing and flexo printing are different.
A. Packaging and trademark printing. This is the main competition area for gravure and flexo printing. The main application products of the flexo are corrugated cardboard, labels, flexible packaging and folding cartons.

a. Corrugated cardboard:
Printing of corrugated cardboard is printed flexibly in more than 85%-98% of foreign countries. Europe and the United States have little difference. The situation in our country is very different: offset printing occupies a considerable share, flexo printing has not become the dominant technology. In this field, the competition between flexo and offset printing is mainly at the same time, which is also one of the most potential application areas for the development of flexographic printing in China. The current difficulties are: the number of corrugated boxes printing manufacturers in China is large, the average size is small, the overall investment capacity is not strong, and the pace of technological upgrading is slow. In the United States, the largest market share of packaging is corrugated cardboard and cartons, so the proportion of flexographic printing is larger in the whole printing process.

b. Labels: Label printing is a large-scale industry in many developed countries, and the use of flexible printing is 85%-95%. In China, labels, especially sticker printing, have developed rapidly in recent years, but the overall scale is still small. This industry should have considerable room for development, and the promotion of flexographic printing can also be expected.

c. Flexible packaging:
Soft packaging is one of the main branches of packaging, and it is also the industry that has the most disputes in terms of flexo and gravure in the world and the greatest difference in development. In this area, the United States uses about 70%-80% flexo, 35%-40% Europe, and Asia (including Japan, South Korea, etc.) this ratio is between 5% and 8%, and this proportion is even higher in China. low. At present, the biggest problems in the promotion of flexographic technology in our country focus on: some attempts in the previous period did not obtain the desired results; understanding of the acceptance of flexographic printing quality and the difficulty of control; equipment (satellite) and the cost of media; technical support Environment and so on.

d. Folding tray:
Although the proportion of flexographic printing in the paper box is different in various countries, there is not much difference: 30%-40% in the United States and 10% in Europe. Of the four types of packaging mentioned above, the proportion of flexographic printing in carton printing may be the lowest. In the field of folding cartons, there are many ways of competition for glue, soft and gravure. However, in China, the narrow-width flexo press is mainly aimed at this field, and the gap between the actual effect and the expected value is not small.

B. Publishing and printing. Gravure and flexo printing are used in two main areas of publishing: newspapers, periodical printing. In the printing of newspapers, the flexographic version has been used between the United States and Europe in the proportion of about 20% -38%, gravure is mainly used for printing newspaper supplements; gravure is the United States and Europe, high-grade, large-volume publications and samples of important printing methods.

C. Other printing. Woodgrain printing is a very fast growing industry in the world in recent years. In this field, gravure printing is used, and the proportion of solvent-based and water-based inks and water-based inks is rapidly increasing. Because of the high level of detail required for grain paper printing (ESA electrostatic assisted ink transfer system) and the large length of the graphics (1500-1900 mm), no other printing methods are used. For similar reasons, transfer printing is basically a gravure printing market. For products with high security performance (especially valuable securities), combination printing has increasingly been adopted at home and abroad in recent years, but the main technology is still gravure.

3. About equipment and materials A. Structure type. The gravure printing machine adopts a unit type structure, and the situation at home and abroad is basically the same; from the perspective of foreign countries, most of the flexographic printing presses have a satellite structure, and the unit type and stacking type only occupy a very small proportion (the ratio of the three is roughly 75%. , 25% and 5%).
Almost all foreign flexible packaging printing, all pre-printed corrugated cardboard, most of the label flexo printing are using satellite flexographic printing presses, folding carton flexo printing presses are increasingly using satellite structure; corrugated carton printing and some label printing The unit type structure is adopted; only a small number of special product flexographic printers use a stacked structure. In China, basically, unit-type flexo presses are used (both domestic and imported), and only a handful of imported devices (less than 3% of the total number of flexo presses) of satellites are available. This is the opposite of the situation abroad.
The advantages of flexographic printing are, to a considerable extent, associated with satellite flexo presses. The advantage of the satellite type relative to the unit type is that the material belt is tightly wrapped on the central impression cylinder, the tension is very stable, the structure is simple, and the distance between the embossing points is short, which facilitates the quality of registration. Therefore, under certain conditions, satellites are the best structure.

B. Number of color groups. Multi-colorization is an important trend, especially in the field of flexible packaging. This is very beneficial to the development of the group printing press. At present, satellite type flexo presses generally have 4, 6, and 8 colors. When the color set exceeds 8 colors, the manufacturing difficulty and cost increase significantly. And the increase/decrease of the color group must be 2 units. Only a few manufacturers in the world can produce 10-color machines. Most of the gravure printers are 8-11 colors. Adding color groups is almost unlimited, and increasing color groups will not increase costs. Therefore, the gravure printing machine is more flexible in adapting to multi-colorization.

C. Manufacturer size. In terms of the international market, manufacturers of general-type flexographic printing presses are smaller in scale, while manufacturers of gravure printing machines and satellite-type flexographic printing presses are larger, mainly because of the large scale (width, speed) and technical content of the equipment. difference.

D. Plate material. Flexographic technology depends to a large extent on media supply. There are well-known manufacturers in the United States and Europe, so the promotion of this technology has favorable conditions. In China, 90% of the flexographic printing plates currently rely on imports, which has affected the promotion of flexographic printing technology to a large extent. (to be continued)