The best way to understand the factors that affect

Understand the factors that affect the quality of bronzing and improve the quality of bronzing

first, 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 usually copper plate or zinc plate. 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 definition of bronzing. 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 carving technology. Making bronzing plate by electric carving can show rich and delicate level changes, and greatly expand the packaging performance. This process has simple beam support and hanging swing of the main shaft, which is conducive to environmental protection. However, the investment of electric carving equipment is large, and the depth of carving is not ideal at present, which is easy to cause bronzing paste. 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 the packaging of fixed and large batch products. At present, there are several units in Shanxi Yuncheng, Beijing and Shanghai that can make it

II. If you want to be good at bronzing equipment, you must first use its tools.

the selection of bronzing equipment is the key factor to determine the quality of bronzing. There are three types of sheet fed bronzing machines: flat pressing, round pressing and round pressing. At present, the flat pressing 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 company, and MK series automatic bronzing and die-cutting machine of Tianjin Youheng machinery industry company. The maximum bronzing speed is 5000 sheet hours. Folljetfbrl04 bronzing machine in stora, Germany, 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 fastest single sheet bronzing equipment 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 production efficiency of round pressing is high, which is especially suitable for bronzing large quantities of live parts. However, due to the difficulty of processing the circular surface of copper plate, the production cost is high, and the heating roller is also more difficult than plane heating. The flattening operation is flexible and convenient, which is more suitable for 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, and it is also more durable than domestic machine, which is more suitable for the processing of fixed batch high-end packaging products. Therefore, the type and batch of products are the key to the selection of bronzing equipment. Whether to have high-grade bronzing and die-cutting equipment such as Bobst has become the preferred condition 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 following is an analysis of some quality problems reflected in the actual operation, so as to scientifically grasp the suitability of bronzing

1. poor hot stamping or inaccurate hot stamping is related to many factors, such as the surface characteristics of the printed piece, the properties of anodized aluminum, hot stamping temperature and pressure

too much powder is sprayed on the surface of the print or the surface contains additives such as adhesive remover and gloss paste, which will hinder the adsorption of anodized aluminum and paper. Solution: remove the powder on the surface or solve it in the printing process. Improper selection of electrochemical aluminum directly affects the fastness of bronzing. According to the size of the bronzing area and the characteristics of the hot stamping material, we should comprehensively consider what type of anodized aluminum to choose. Domestic anodized aluminum is mainly the peacock brand series produced by Shanghai Shenyong bronzing Materials Co., Ltd., while imported anodized aluminum is mainly the PM and LK series of Kurtz, Germany, the A, K, H series of Japan, and the SP series of Kolon, South Korea. According to our practice and testing, the selection of anodized aluminum can mainly refer to the following categories: the gilding anodized aluminum on ordinary products has 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; 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. Failure to correctly master the bronzing equipment and the match between the pressing time and the hot stamping temperature will affect the fastness of hot stamping and the clarity of the image 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 contacts, and the hot stamping temperature is higher than the round flattening or flat flattening. Generally, the temperature of round pressing and hot stamping is 190 ℃ ~ 220 ℃, the round flattening is about 130 ℃ ~ 150 ℃, and the flat flattening is about 100 ℃ ~ 120 ℃. Of course, the hot stamping time, hot stamping temperature and production efficiency are also restricted by the transfer performance of anodized aluminum to a large extent

2. Reverse pulling insulation material becomes leveling material. Reverse pulling refers to that after hot stamping, anodized aluminum pulls away printing ink or varnish on printed parts. This is mainly because 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 weak combination of the ink and UV oil on the surface of the print and the surface of the paper. Solution: bronzing after printing is dry. In addition, electrochemical aluminum with low separation force and excellent heat transfer can be selected

3. after pasting and hot stamping rdquo; Electrochemistry aluminum color changing paste plate is mainly caused by poor production of bronzing plate, loose installation of electrochemistry aluminum or incorrect foil of electrochemistry aluminum. The color change of anodized after hot stamping is mainly caused by high hot stamping temperature. In addition, anodized wrinkling is also easy to cause uneven hot stamping and discoloration, which 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 before hot stamping

4. The process arrangement is inappropriate, which destroys the surface gloss of anodized aluminum, and the graphic outline is 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, so 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 avoid losing the gold powder and sticking to the edge of the picture and text, resulting in virtual phenomenon

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. The correct process is to cover the film before bronzing, and select the anodized aluminum matching opp

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 to improve the quality of bronzing