With the improvement of the national economy and the development of the printing and packaging industry, people require product packaging: high-end, exquisite, environmentally friendly, and personalized. In the post-printing processing of packaging products, the electrochemical aluminum hot stamping process is loved by people because of its unique surface finishing effect. It is used in high-end packaging such as banknotes, cigarette labels, medicines, and cosmetics. Electrochemical aluminum hot stamping refers to the hot stamping process of hot stamping, silver foil and other hot stamping materials. For the convenience of discussion, the general name of electrochemical aluminum hot stamping is used below. Hot stamping mainly has two functions. One is surface decoration to increase the added value of the product. It is our country's national tradition to love celebrations and resplendent things. The hot stamping and embossing process are combined to show its luxury. The second is to give the product high anti-counterfeiting performance, using holographic positioning and hot stamping trademark logos to prevent counterfeiting and protect the brand. At the same time, hot stamping can very well express the personalization of product packaging and is safe and environmentally friendly. Therefore, many high-end packaging adopts hot stamping process, so how to improve the quality of hot stamping? This article will discuss from the following aspects. 1. Hot stamping version High-quality hot stamping version is the primary factor to ensure the quality of hot stamping. At present, the production of hot stamping plates mainly uses photographic etching technology and electronic engraving technology, and the materials are commonly used copper plates or zinc plates. The copper plate is made of fine material, and its surface smoothness and heat transfer effect are better than that of the zinc plate. Using high-quality copper plate can improve the gloss and outline clarity of the hot stamping graphics. The traditional photoetching technology is simple and low-cost to produce hot stamping plates. It is mainly used for text, thick lines, and general images. For finer hot stamping plates with uneven thickness of graphics and text, it is necessary to use secondary etching or electric engraving technology. Electric engraving to produce hot stamping plates can express rich and delicate layer changes, which greatly expands packaging expressive capabilities. This process is beneficial to environmental protection, but the investment in electric engraving equipment is relatively large, and the current engraving depth is not ideal enough, which can easily cause "paste" of hot stamping. The production technology of holographic anti-counterfeiting hot stamping plates is relatively high. In the past, they were mainly produced in Taiwan or abroad. The plate making cycle was long and they were only used for the packaging of fixed and large-volume products. At present, there are several domestic units in Yuncheng, Shanxi, Beijing and Shanghai that can produce it. 2. Hot stamping equipment “If a worker wants to do his job well, he must first sharpen his tools.” The selection of hot stamping equipment is a key factor in determining the quality of hot stamping. There are three types of sheet-fed hot stamping machines: flat flattening, round flattening, and round flattening. Currently, the flat flattening machine is the most widely used, mainly including: Shanghai Yahua Printing Machinery Co., Ltd. TYM series die-cutting and hot stamping machines. The machines used are the TYMl020 automatic hot stamping and die-cutting machine of Tangshan Yuyin Group Company and the MK series automatic hot stamping and die-cutting machine of Tianjin Youheng Machinery Industry Company. The maximum hot stamping speed is 5,000 sheets/hour. Germany's STEUER FOLLJET FBRl04 hot stamping machine is a representative of round pressing. Using the design concept of an offset printing machine, the maximum hot stamping speed can reach 10,000 sheets/hour. It is currently the fastest single-sheet hot stamping equipment in the world. The three embossing methods of round press, round press and flat press, each have their own advantages and disadvantages: round press and round press hot stamping are implemented with linear pressure, the total pressure is small, and can be easily completed with relatively small pressure. Large area of ??solid hot stamping, smooth movement, and high production efficiency of round pressing, especially suitable for hot stamping of large quantities of work. However, due to the difficulty of processing the arc surface of the copper plate, the production cost is higher, and the heating roller is also more difficult to heat than the flat surface. The flattening operation is flexible and convenient, and is more suitable for short-run products. Compared with imported hot stamping equipment, domestic hot stamping equipment has obvious advantages in performance and price. The price of domestic machines is only equivalent to 1/5 to 1/4 of the price of similar foreign products, but the imported machines have better overprint accuracy, stability, and functions. It is obviously better than the domestic machine and more durable than the domestic machine. It is more suitable for the processing of fixed batches of high-end packaging products. Therefore, product type and batch size are the keys to determining the selection of hot stamping equipment. Whether you have high-end hot stamping and die-cutting equipment such as BOBST has become the first choice for customers in the industry. 3. Hot stamping suitability: The so-called hot stamping suitability refers to the matching between the model selection of anodized aluminum and hot stamping speed, temperature, pressure and other factors. When equipment and other hardware are fixed, correctly grasping the hot stamping suitability is the most important means to improve the quality of hot stamping. The following is an analysis of some quality issues reflected in actual operations, in order to scientifically grasp the hot stamping suitability. 1. The hot stamping fails or is not accurate. This is related to various factors such as the surface characteristics of the printed parts, the properties of the anodized aluminum, the hot stamping temperature and pressure, etc. ① The surface of the print is sprayed with too much powder or the surface contains additives such as adhesive remover and gloss paste, which will hinder the adsorption of anodized aluminum and paper.

Solution: Surface powder removal treatment or solution in the printing process. ② Improper selection of anodized aluminum directly affects the hot stamping fastness. What type of anodized aluminum should be selected based on the size of the hot stamping area and the characteristics of the hot stamping material. Domestic anodized aluminum is mainly the Peacock brand series produced by Shanghai Shenyong Hot Stamping Materials Co., Ltd., and imported anodized aluminum is mainly PM and LK series from Germany's Kurz (KURZ), Japan's A, K, H series, and South Korea's KOLON's SP series. . According to our practice and testing, the selection of anodized aluminum can mainly refer to the following categories: hot stamping (generally ink color) on ordinary products, including 88-l type, KURZ PM type; cigarette packs, cosmetics and other thick ink printed matter (including printing There are 88-2 type electrochemical aluminum for hot stamping (gold, printing silver); 88-3, 88-4 type, PM288, etc. for hot stamping fine handwriting on cigarette labels, cosmetic packaging, etc.; suitable for OPP or PET laminated paper As well as cardboard, glazed paper and other products with UV ink, hot stamping electrochemical aluminum includes 88-4 type, K series, LK series, and SP series. ⑧ Failure to correctly grasp the hot stamping equipment and the matching between hot stamping time and hot stamping temperature will affect the hot stamping fastness and the clarity of the image and text outline. Due to different equipment and hot stamping materials, the hot stamping time and hot stamping temperature are different. For example, if the high-speed rounding machine is fast and the nip line is in contact, the hot stamping temperature will be higher than that of rounding or flattening. Generally speaking, the temperature for round pressing and hot stamping is between 190°C and 220°C, for round pressing and hot stamping, it is about 130°C and 150°C, and for flat pressing and stamping, it is between 100°C and 120°C. Of course, hot stamping time, hot stamping temperature and production efficiency are also largely restricted by the transfer performance of anodized aluminum. 2． Reverse pull Reverse pull means that the anodized aluminum pulls away the printing ink or varnish after hot stamping. The main reason for this is that the ink on the surface of the printed product is not dry or the UV and other post-processing treatment on the surface of the printed product is improper, resulting in the ink and UV oil on the surface of the printed product not being firmly bonded to the surface of the paper. Solution: Wait for the printed matter to dry before hot stamping. In addition, anodized aluminum with lower separation force and excellent heat transfer properties can be used. 3. Discoloration of the anodized aluminum after pasting and hot stamping. The pasting is mainly caused by poor production of the hot stamping plate, loose installation of the anodized aluminum or incorrect foil routing of the anodized aluminum. The discoloration of anodized aluminum after hot stamping is mainly caused by the hot stamping temperature being too high. In addition, wrinkles of anodized aluminum can easily cause uneven color stacking and discoloration of hot stamping, which can be solved by appropriately lowering the temperature. For the round flattening machine, a fan can be installed at the foil feeding area to keep the foil flowing and to prevent the anodized aluminum from touching the hot stamping plate and causing it to burn before hot stamping. 4. Improper process arrangement destroys the surface gloss of anodized aluminum and makes the outline of graphics and text appear blurry. For hot stamping that requires lamination processing, people often worry that the gold foil is easy to rub off, so they hot stamp first and then laminate. This can easily cause: ① The film (especially the matte film) will destroy the gloss of the anodized aluminum surface, and it is not advisable to use water-soluble glue for lamination. , otherwise it will cause the surface of the anodized aluminum to turn black, and it is easy to cause gold powder to stick to the edges of the graphics and text, causing blurring. ② After hot stamping, it will be dented due to pressure. In addition, the glue cannot easily penetrate the surface of the anodized aluminum, which can easily cause the OPP and paper to separate from the hot stamping area and affect the product quality. The correct process is to laminate first and then hot stamp, and choose anodized aluminum that matches the OPP.