How to improve the quality of bronzing
with the improvement of the national economy and the development of the printing and packaging industry, people require the packaging of products: high-end, exquisite, environmental protection, personalized material market. In the post press processing of packaging products, anodized hot stamping process is loved by people because of its unique surface finishing effect. It is applied to high-end packaging such as banknotes, cigarette labels, drugs and cosmetics. Printing plays a decisive role in guiding the development of the industry, enhancing industry self-discipline, improving technical level, increasing international exchange, expanding utilization and cooperation, and expanding publicity and promotion. Anodized hot stamping refers to the hot stamping process of bronzing, silver stamping and other hot stamping materials. For the convenience of discussion, the following bronzing is collectively referred to as anodized hot stamping printing tools. Bronzing has two main functions: one is surface decoration, which improves the value-added printing technology of products. Loving festivity and resplendence is China's national tradition. Bronzing and embossing are combined to show their splendor; Second, the products are endowed with high anti-counterfeiting performance. Holographic positioning and hot stamping trademark identification are adopted to prevent counterfeiting and protect the famous brand in Central China. At the same time, bronzing can show the individualization of product packaging and the safety and environmental protection printing market. Therefore, many high-end packaging have adopted the bronzing process, so how to improve the quality of bronzing? This paper discusses the printing market from the following aspects
first, bronzing plate high-quality bronzing plate is the primary factor to ensure the quality of bronzing.
at present, the production of bronzing plate mainly adopts photographic corrosion process and electronic engraving technology, and the materials are commonly copper plate or zinc plate equipment consumables. Copper plate material is fine, and the surface smoothness and heat transfer effect are better than zinc plate. The use of high-quality copper plate can improve the gloss and outline clarity of bronzing pictures and texts, and the central printing. The traditional photographic etching technology is simple and low-cost, which is mainly used for text, thick lines and general images; For fine, uneven thickness bronzing plates, it is necessary to use secondary deep burn or electric engraving technology to print the market. Electric engraving can show rich and delicate level changes in the production of bronzing plate, which greatly expands the performance of packaging. This process is conducive to environmental protection, but the investment in electric engraving equipment is large, and the depth of engraving is not ideal at present, which is easy to cause printing in the middle of bronzing paste plate. Holographic anti-counterfeiting bronzing plates have high technical requirements. Previously, they were mainly made in Taiwan or abroad. The plate making cycle is long, and they are only used for packaging equipment consumables for fixed and large batch products. At present, there are several units in Shanxi Yuncheng, Beijing and Shanghai that can produce printing markets
second, if you want to do a good job of bronzing equipment, you must first use its tools.
the selection of bronzing equipment is the key factor that determines the quality of bronzing printing alliance. There are three types of sheet fed bronzing machines: flat press, round press and round press. At present, the flat press machine is the most widely used, mainly including: tym series die-cutting and bronzing dual-purpose machine of Shanghai Yahua Printing Machinery Co., Ltd., tyml020 automatic bronzing and die-cutting machine of Tangshan Yuyin group, and MK series automatic bronzing and die-cutting machine of Tianjin Youheng machinery industry company. The maximum bronzing speed is 5000 sheet hour printing market. Germany stora folljet fbrl04 bronzing machine is a representative of round pressing. Using the design concept of offset printing machine, the maximum hot stamping speed can reach 10000 sheet hours. At present, it is the equipment and consumables with the fastest single sheet bronzing speed in the world. The three stamping methods of round pressing, round pressing and flat pressing have their own advantages and disadvantages: the implementation of round pressing and round pressing hot stamping is linear pressure, and the total pressure is small. It can easily complete large-area field bronzing with relatively small pressure, and the movement is stable. Moreover, the round pressing type has high production efficiency, which is especially suitable for bronzing large quantities of live parts. However, due to the great difficulty in processing the circular surface of copper plate, the production cost is high, Heating roller is also more difficult than plane heating equipment consumables. The flattening operation is flexible and convenient, which is more suitable for the material market of short version products. Compared with imported bronzing equipment, domestic bronzing equipment has obvious advantages in performance and price. The price of domestic machine is only equivalent to L5 ~ 14 of the price of similar foreign products, but the overprint accuracy, stability and function of imported machine are significantly better than domestic machine. It is also more durable than domestic machine, which is more suitable for the processing and printing technology of high-end packaging products with fixed batch time and short time. Therefore, product type and batch are the key printing market to determine the type selection of bronzing equipment. Whether we have high-grade bronzing die-cutting equipment such as Bobst has become the preferred printing tool for customers in the industry
III. bronzing suitability
the so-called bronzing suitability refers to the model selection of electrochemical aluminum and the matching between bronzing speed, temperature, pressure and other factors. When the equipment and other hardware are fixed, correctly mastering the bronzing suitability is the most important means to improve the bronzing quality. The quality of the object byte is too important. The following is an analysis of some quality problems reflected in the actual operation, so as to scientifically grasp the bronzing suitability printing alliance
1. There are many factors related to the printing market, such as the surface characteristics of printed parts, the properties of anodized aluminum, hot stamping temperature and pressure
too much powder is sprayed on the surface of the print or there are additives such as adhesive remover and gloss paste on the surface, which will hinder the adsorption of anodized aluminum and paper for central printing. Solution: remove the powder on the surface or solve the printing alliance in the printing process. Improper selection of electrochemical aluminum directly affects the fastness of bronzing and printing in the middle. According to the size of the bronzing area and the characteristics of the materials to be bronzed, we should comprehensively consider what type of electrochemical aluminum equipment consumables to choose. Domestic electrochemical aluminum is mainly the peacock brand series produced by Shanghai Shenyong bronzing Materials Co., Ltd., while imported electrochemical aluminum is mainly the PM and LK series of Kurtz, Germany, the A, K, H series of Japan, and the SP series of printing tools of Kolon, South Korea. According to our practice and testing, the selection of electrochemical aluminum can mainly refer to the following categories: the size of gilded polystyrene board test board or cement mortar test board on ordinary products: 70X70X20mm, 5 pieces of electrochemical aluminum, including 88l type and Kurz PM type; There are 882 types of gilding anodized aluminum for thick ink printed materials such as cigarette bags and cosmetics (including gold and silver printing); There are 883, 884 types, pm288, etc. of electrochemical aluminum for fine handwriting hot stamping of cigarette labels, cosmetics packaging, etc; It is suitable for hot stamping of OPP or pet coated paper, cardboard with UV ink, polishing paper and other products. Anodized aluminum has 884 type, K series, LK series, and SP series printing technology. Failure to correctly master the bronzing equipment and the match between the pressing time and the hot stamping temperature will affect the hot stamping fastness and the clarity of the picture and text outline. Due to different equipment and materials to be hot stamped, the pressing time and hot stamping temperature are different. For example, the high-speed rotary press is fast, the stamping line is in contact, and the hot stamping temperature is higher than that of the round flattening or flat flattening equipment consumables. Generally, the temperature of round pressing and hot stamping is 190 ℃ ~ 220 ℃, the round pressing is about 130 ℃ ~ 150 ℃, and the flat pressing is about 100 ℃ ~ 120 ℃ in the printing market. Of course, the hot pressing time, hot stamping temperature and production efficiency are also restricted by the transfer performance of anodized printing tools to a large extent
2. Reverse pull refers to the process that anodized aluminum pulls printing ink or varnish away from central China after hot stamping. The main reason for this is that the ink on the surface of the print is not dry or the post-processing treatment of UV on the surface of the print is improper, resulting in the equipment consumables caused by the weak combination of the ink and UV oil on the surface of the print and the surface of the paper. Solution: bronzing printing technology after printing is dry. In addition, it can be printed in the middle of electrochemical aluminum with low separation force and excellent heat transfer
3. Paste plate and anodized discoloration after hot stamping paste plate is mainly a printing tool caused by poor production of bronzing plate, loose installation of anodized plate or incorrect foil feeding of anodized plate. The discoloration of anodized after hot stamping is mainly caused by high hot stamping temperature, which causes equipment consumables. In addition, anodized wrinkling is also easy to cause uneven color stacking and discoloration in hot stamping. The middle printing can be solved by appropriately reducing the temperature. For the round flattening machine, a fan can be installed at the foil feeding place to keep the foil floating, so as to avoid the electrochemistry aluminum touching the bronzing plate and scorching the printing technology before hot stamping
4. Improper process arrangement destroys the surface gloss of electrochemical aluminum, and the picture and text outline makes the material market false. For bronzing that requires film covering processing, people often worry that the gold foil is easy to be wiped off and hot stamping before film covering, which is easy to cause:
① the film (especially the matte film) will damage the surface gloss of anodized aluminum, and it is not suitable to use water-soluble glue to cover the film, otherwise it will cause the surface of anodized aluminum to blacken, and it is very easy to cause the gold powder to stick to the edge of the picture and text, resulting in the phenomenon of virtual material market
② after bronzing, it is sunken due to pressure, and the glue is not easy to penetrate the surface of anodized aluminum, which is easy to cause the separation of OPP and paper at the bronzing place and affect the product quality and material market. The correct process is to cover the film first and then bronze, and choose the anodized aluminum matching OPP in Central China
in short, there are many factors that affect the quality of bronzing. To make a high-quality bronzing plate, correctly mastering the bronzing suitability is the key printing technology to improve the quality of bronzing