Seven die cutting technology for flexographic printing
The die-cutting of flexographic printing is divided into two types: semi-cut and full-cut. Semi-cut die cutting does not allow the die-cut material to be formed separately due to the use of a function or other specific conditions. One form is that the product webs are connected to each other with continuous dot-like voids without separation and disintegration; the other form is that the die cutting of the composite material is limited to surface prints, and the carrier of the laminate material is intact. The latter is a typical example of die cutting of various types of adhesive labels.
Full-thickness die-cutting is the final product or semi-finished product that is divided into the same number of combinations as the layout type after the die-cutting of the printed matter and the substrate, but has a different surface area from that of the original printing grid. Full-cutting die-cutting is applied to the die-cutting of packaging products other than self-adhesive labels, such as cartons, paper cups, beer labels, and instant noodle bowl lids.
Eight, magnetic die cutting technology
The magnetic roller and magnetic plate in the magnetic die-cutting technology (die cutter plate) are mainly manufactured by using the principle of magnetic field, and the individual permanent magnet pieces are arranged in polarity, and are embedded in the groove of the stainless steel roller body, due to the excellent polarity distribution. The magnetic roller generates a strong magnetic field and permanent magnet force, and the magnetic plate suction is used to adsorb the die cutter plate on the surface of the roller body.
The magnetic die-cutting technology has the following remarkable features compared with other die-cutting technologies: 1 The excellent polarity distribution makes the magnetic roller have strong permanent magnet force and can perform die-cutting at a very high speed. 2 High precision of magnetic roller processing, concentricity error can be controlled within ±21μm. 3 Use the positioning line to install the die cutter, and the dismountable die cutter is very flexible and convenient. 4 The use of a wide range of flexible, especially suitable for the same size but many varieties of fancy. 5 According to the amount of die-cutting requirements, different die-cutting materials can be produced using different processing techniques, which can greatly reduce costs. 6 die cutter version of the high precision machining, good flatness, no need to process the back of the knife, knife height error is 3μm. 7 can process any pattern and point knife line, different cutting height, full cut through and half cut through die cutter version. 8 Because the die cutter is limited by the height of the tool and the gap of the magnetic roller, it is usually not possible to grind the blade after it has worn out, and the integral die cutting roller can usually be ground 3 to 5 times. 9 magnetic die cutter version is not suitable for high-volume, single-order, more suitable for small-lot, multi-order die-cutting products.
Magnetic die-cutting technology has been widely used in foreign countries. From die-cutting die-cutting, in-mold label die-cutting to die-cutting and punching of packaging boxes, high application ratios have been achieved in some fields. For example, in developed countries in Europe and America, at least 60% of the adhesive products use magnetic die-cutting technology, while China is currently mainly die-cut in flat-flattening mode.
At present, the number of domestic imported printing equipment is increasing day by day, and people's requirements for packaging materials and printed matter are getting higher and higher, and there are also growing concerns about the health standards and health requirements. Therefore, the use of non-toxic environmentally friendly ink flexographic printing methods The proportion will increase. It is expected that by 2010, the proportion of flexographic printing in China will reach at least 8% to 10%, and these flexographic printing opportunities will increasingly use round-bore die cutting technology. The development of circular press die cutting technology will further expand the application of magnetic die cutting technology. It is believed that in the near future, magnetic die cutting technology will certainly gain its rightful place in the field of domestic die cutting.
Nine, laser digital etching processing
Computer-controlled laser manufacturing is an important symbol of the country’s industrial image. The international community, especially the developed countries, attaches great importance to the application of laser manufacturing technology. As early as in the early 1970s, some companies began to research and develop high-quality, high-efficiency laser technologies to design die-cutting new processes and achieved certain successes.
The laser digital etching process refers to etching the processed material by laser beam (vaporization of the material irradiated by the laser) according to the digitized information, instead of the traditional die-cutting process. Typical laser digital etching systems include: carbon dioxide lasers and scanners, power units, coolers, power controllers, software, smoke chambers, etc., if not integrated with printing machinery or processing lines, then there are processing rolls. Operational system: The processing of high registration accuracy may also require an electronic display control system. The general estimate is that the investment will be between 180,000 and 300,000 U.S. dollars. In the old system, the laser was fixed, and the material processing table was moved in the X and Y directions, so the speed was limited and it was difficult to welcome. The new system uses a scanning galvanometer to drive the laser beam and the rotating mirror so that the laser beam can be fired in all directions, and the processing speed is also greatly increased, which can reach a range of 80 to 600 inches per second. For the reel-to-reel laser processing system, it is also possible to perform intermittent repetitive processing, ie, laser beam is intermittently repetitively processed according to the programmed pattern information (as in the case of a continuous dryer). For the depth of the etched material to be processed, as long as the etching speed or laser parameters are adjusted, it can be flexibly adjusted (or completely penetrated, or lightly spotted, for indentation or film removal).
Obviously the advantages of this new laser digital etching process are easy to understand;
1 Flexibility: In any shape, no mold is required. As long as a program is programmed, the laser beam can be programmed to cut the shape and depth of the die-cut, and it can also be changed in operation without tools. This is Personalization of packages or trademarks or small batches opens the door to convenience.
2 Accuracy: The tolerance does not exceed three-thousandths of a millimeter. It also compensates for errors that occur between printing and post-processing because lasers can compensate for adjustments, whereas in conventional die-cutting, the die is difficult to change after it is fixed.
3 high production efficiency: Because do not need to make molds, just make up the program, the task to follow suit, save time and save time. Adjustments can also be made at the last minute before starting processing without affecting production. Regardless of simple or complex machining shapes, the processing costs are the same and the time taken is basically the same. Its processing speed can basically match with the speed of digital printing, and can form a continuous machine production.
4 Economic benefits: It is not necessary to prepare molds. It does not matter if the processing tasks are large or small, and the business sources are also broadened. In the traditional die-cutting process, not only the die variety (such as flat pressure type, wheel pressure type, hole punching, eye-opening, indentation, etc.), but also the supporting tools are complicated. Now all can be omitted.
5 Aesthetic effects: Laser etching is stress-free, so no traces are left on the processed material; the pressure-sensitive trademark is not only scarce, but also easy to peel off.
Laser die-cutting technology has a wide range of applications. First, it can be used for die cutting of traditional trademarks, stickers, and cards. This is also its main application area.
Second, it can be used for anti-counterfeiting. For example, the production of relief, shaped holes and latent effects. Foreign anti-counterfeiting industry tried to use laser die cutting to produce relief effect around 1997. The stamp industry is trying to use it for perforating stamps, which can not be imitated by mechanical punching. It can also play a security role. For example, tickets for the Asian Cup football match have a higher price, so we must consider security. Laser drilling for anti-counterfeiting should be very effective. The application of the latent image is also a technology that needs to be tapped. If it is used well, it will have a certain impact on the die-cutting industry. For example, after a pattern is engraved on paper, the paper on that part is thinner than other parts. If a layer of special material is applied on the surface of the paper, the thickness is the same, but there is a latent image that can play a role. Similar effects to watermarks.
Thirdly, by using the dot-mapping principle, laser ablation produces dense holes that can also form images. This technique has been applied experimentally. A few years ago, foreign countries had already implemented the stamps, but only as proofs.
The emergence of new technologies certainly cannot be perfect at once. In some cases, it is still necessary to continue research and improvement. For example: the variety of packaging materials, thickness varies, performance will also have access, laser etching, how to etch the residence time or laser energy, grasping just right, so that the edge of the etching smooth, deep and shallow, there is also a never-familiar to Skilled process. In addition, it also has certain limitations, such as: metal material is not suitable; there are certain deficiencies, such as: laser incision microstrip bevel, some materials may change color, some plastics may be slightly visible burrs and so on. But in general, some experts predict that in the past 10 years, the traditional die-cutting process may disappear in some large packaging and processing companies. In the vast market of packaging products, laser etching processing technology will be increasingly welcomed and promoted. This is another leap in laser technology for die cutting.
X. Anti-counterfeit molded laser holographic technology
Molded laser holography can be extensively combined with ordinary printing techniques. The surface of the molded material can be printed with a fluorescent ink, a temperature change ink, etc. to make an open moldable laser hologram mark. The ink can be printed on the surface of the molded material, and then the scraped-off ink can be used to make a stenciled laser holographic mark. Combining ordinary printing marks with molded laser holographic products can be used to make the laser stealth anti-counterfeiting marks; the transfer of the embossed holograms on the holographic film to the paper base can be made into a hologram paperboard instead of the ordinary paper jam. Ordinary printing can achieve the best combination of laser holography and ordinary printing. Molded laser holographic technology and anti-counterfeiting of telephone code information have made anti-counterfeiting products a new level.
Eleventh, the new development of molding technology
First, with the wide application of computer technology and digital technology, die-cutting and indentation technology is developing toward high speed, high precision, multi-function, online and digital. High-precision, high-speed molding technology has been developed. At the same time, multi-functional die-cutting and indentation technology is continuously being improved. Die-cutting indentations are put together with hot stamping, embossing, and embossing. This is also the future of die-cutting pressure. One of the development directions of trace technology.
Second, three-dimensional effect die cutting technology. The use of glazing, hot stamping, hologram effect, embossing, and die-cutting indentation make commodity packaging a distinctive feeling for commodity buyers and an important task for post-press processing. The three-dimensional effect die-cutting technology is a brand-new surface finishing technology, which combines the die-cutting method with other post-printing techniques to get more personalized effects, such as metallic luster and pearlescent effect, and partial gloss effect, etc. At the same time, consumers can also be impressed by the effect of cutting off some of the contours. In the decoration of books and magazines, the cut-out part will serve as a display window for pictures, and it will also receive very peculiar effects. Multi-layer folding can also be used to create suspense, causing readers to curiosity, so this method can better highlight the theme of books and magazines. In addition, the decoration around the window is also one of the highlights, and the transparent film can be attached to make the die-cut part like a complete glass window. This die-cutting method is applicable to many materials such as paper, cardboard, corrugated cardboard, films and other plastics, cork, aluminum foil and fabrics.
This paper reviews the traditional die-cut indentation technology and looks forward to some new technologies. Although the traditional die-cutting technology is relatively mature and has been widely used, there are some disadvantages such as inaccurate position of die-cutting indentation, frying lines, fluffing, etc., which are always prone to occur, and do not meet consumer requirements for special packaging. With the continuous development and improvement of new die-cutting technology, these disadvantages will be overcome more or less, and more beautiful and unique packaging products can be produced. In this way, printing and packaging companies will be able to produce more exquisite packaging with the highest efficiency and best results, thereby enhancing the competitiveness of enterprises.
Source: Guangdong Printing