A brief talk on the new technology of bronzing

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Talking about the new process of bronzing

1 background

energy conservation and emission reduction is the eternal theme of a national sustainable development strategy. In recent years, with the rise of the trend of environmental protection printing, the printing technology of energy conservation and emission reduction has attracted more and more attention from the industry. Among these technologies, the roll to roll printing production process has received special attention because it can save a large paper cost. According to statistics, the roll to roll production method can save more than 2% of the paper cost compared with the sheet fed production method because it has no bite edge and drag edge, This is a considerable cost for paper packaging, especially cigarette package printing, which takes paper as the main cost

however, the roll to roll production mode of web paper has not become the mainstream production mode of cigarette packet printing that transfers heat to cutting tools for so many years, which is directly related to the relatively lagging post press processing technology, especially the hot stamping liquid crystal real-time display of experimental force, displacement, peak value, running state, running speed and other technologies. For a long time in the past, most of the products packaged in cigarette packs and reels were low-grade cigarettes. The printing process of these cigarette packs was relatively simple and basically pure printing products. However, with the popularity of bronzing technology, some cigarette packs packaged in reels began to have the transformation requirements of adding bronzing process in order to improve the packaging grade. Due to this demand, several farsighted equipment developers at home and abroad began to develop supporting wire bronzing units on printing machines for commonly used cigarette packs and achieved success, but this was also limited to simple flat ironing. However, as a mainstream product, most of the packaging of medium and high-end cigarette brands have embossing and holographic positioning bronzing processes, or even both at the same time. Moreover, the production process and quality inspection of products with embossing and holographic positioning from roll to roll will be a major problem faced by printing equipment factories and printing factories. Next, we will conduct some preliminary research and Discussion on the solution of these problems from the aspects of equipment, plate making, quality inspection, process route, etc

2 bronzing equipment

at present, the main manufacturers at home and abroad that can develop professional roll to roll bronzing equipment for cigarette bag production are Swiss boster company, Swiss gies company, Tianjin evergreen company and Wuhan Jincai company. Among these companies, Swiss boster company and domestic Wuhan Jincai company can develop roll to roll round bronzing machines, Swiss gies company and domestic Tianjin evergreen company can develop roll to roll flat bronzing machines, which can basically realize roll to roll convex ironing + holographic positioning ironing. For different product structures, the round pressing and flattening roll to roll bronzing machines have their own advantages. The roll to roll round bronzing method belongs to line contact hot stamping, which has fast bronzing speed and high production efficiency, and is especially suitable for flat ironing, fine line ironing and holographic positioning ironing with large area; The bronzing method of roll to roll flattening belongs to face-to-face contact bronzing, and the bronzing speed and production efficiency are lower than those of round pressing, but it has advantages in embossing adaptability and hot stamping effect, and its plate making cost is relatively low. Due to historical reasons, most of the embossing processing of existing cigarette bag products is completed on a single sheet flattening bronzing machine, while the embossing of flat pressing and round pressing are slightly different in effect. Therefore, For products with sample tracking requirements, customers often consider using roll to roll flat bronzing machines

3 plate material

for the production of bronzing plate, if the original bronzing method is changed from round pressing sheet metal bronzing to round pressing roll to roll bronzing, or from flat pressing sheet metal bronzing to flat pressing roll to roll bronzing, the original production plate can be used. If the original hot stamping method is changed from round pressed sheet fed hot stamping to flat rolled roll to roll hot stamping, or from flat pressed sheet fed hot stamping to round rolled roll to roll hot stamping, the plate making process needs to be adjusted according to the embossing effect of the product to make it as close as possible to the sample sheet. With regard to the current plate making technology at home and abroad, such a transformation is not too difficult

for anodized aluminum, if the original hot stamping method has not changed in the round and flat pressing, anodized aluminum can continue to use the original production of anodized aluminum. If the original hot stamping method is changed from round pressing to flat pressing or vice versa, the glue formula of anodized aluminum needs to be adjusted. It can be basically solved by several tests with the cooperation of relevant electrochemical aluminum manufacturers

4 quality inspection

one of the most important links in the production process of roll to roll embossing + holographic positioning ironing is quality inspection. Compared with the quality inspection of sheet fed paper, the biggest weakness of roll to roll quality inspection is that the product cannot be sampled in the process, which is also one of the important reasons why the application of roll to roll bronzing technology lags behind the application of sheet fed bronzing technology. Therefore, the production of roll to roll embossing + holographic positioning ironing should be fully realized, The first is to solve the problem of quality inspection. However, during the detection process, the change of the rainbow effect of the hologram in the holographic anodized aluminum is not a small test for the detection, but also a difficult topic to overcome for a period of time, especially if the convex ironing and holographic positioning ironing of different anodized aluminum need to detect their quality effects at the same time. At present, three companies at home and abroad claim to have developed quality inspection systems that can detect holograms. They are Israel AVT quality inspection system, Germany e+l quality inspection system and Beijing Lingyun quality inspection system. These three quality inspection systems can be installed on the roll to roll bronzing equipment for synchronous detection, and can record, alarm and display the quality problems in the bronzing process. They can also determine their positions through the rewinding system and complete the production of finished reels by replacement. Among the three quality inspection systems, Israel AVT quality inspection system and Germany e+l quality inspection system adopt the system quality inspection method, while Beijing Lingyun quality inspection system adopts the dual system quality inspection method. From the experimental results, the dual system quality inspection method is better in detecting all kinds of subtle defects in hologram bronzing. Therefore, when selecting the roll to roll convex bronzing + holographic positioning bronzing quality inspection system, it is suggested to select the dual system to obtain the stress-strain curve quality inspection method

5 selection of process route

for the reel products with holographic positioning ironing + embossing, which are relatively difficult in the current high-quality cigarette bags, the best process route we suggest is: multi-color gravure + static image quality inspection offline holographic positioning ironing + embossing double station bronzing + dual system quality inspection offline strip rewinding single roll secondary quality inspection rewinding splicing finished products into storage

6 thinking about the existing problems

1) if the round pressing double station bronzing is selected, the effect on the convex part will be worse than that of the original flat pressing. If you choose flat pressing double station bronzing, there will be some problems in the registration of holographic positioning ironing when the layout is large, and it is also a problem for such reel products. Of course, an idea is put forward here, whether one station in a set of equipment can be used for round pressing and the other station is used for flat pressing, so as to solve the above problems, which requires further research and test by the manufacturer of bronzing equipment

2) production process

① after the soft paper is embossed and ironed, after rewinding with high tension, the embossing effect will be affected to a certain extent, which will be slightly different from the original

② whether the asymmetric convex ironing will affect the normal packaging production of cigarette factory's cigarette packaging machine due to the size of the reel

above, we mainly carried out preliminary research and Discussion on the cigarette bag production process of roll to roll holographic positioning ironing + embossing ironing on the basis of relevant experiments. There may be many problems to be solved in the future batch production, but if this new bronzing process can be realized in batch production, it will have a good effect on improving production efficiency, saving raw materials, promoting energy conservation and emission reduction

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allen bradley 1734-aentr
allen bradley 1769-iq16

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