Bronzing and three-dimensional bronzing
1. bronzing
Bronzing is the use of a certain pressure and temperature, using the template installed on the hot stamping machine, so that the printed matter and the hot stamping plate are pressed together in a short time, and the metal foil or color pigment foil is transferred to the quilt according to the graphic requirements of the hot stamping template The processing technology of hot material surface. Because hot stamping is mainly based on gold and silver, it is often called hot stamping. This technology is an important process to increase the visual effects and grades of labels, trademarks, cigarette bags, wine bags and various high-end packaging boxes. It can be divided into hot stamping and printing and hot stamping and printing. Hot stamping before printing is to stamp the electrified aluminum foil layer on the blank substrate first, and then print graphics on the surface of the aluminum foil layer, which is mostly used for packaging prints that require large area hot stamping. The first printing and then the hot stamping is on the printed matter that has been printed, and the desired pattern is stamped on the part that needs to be stamped. This is a process that is currently widely used. From the hot stamping method, it can be divided into hot stamping technology and cold stamping technology. Hot stamping technology is the above-mentioned hot stamping process that requires a certain temperature and pressure to complete the transfer of electrochemical aluminum foil. The cold hot stamping technology is a process of applying UV adhesive to the parts of the printed matter that need to be hot stamped, and transferring the electrochemical aluminum foil to the surface of the packaging printed matter under a certain pressure. These two methods have their own characteristics to meet the requirements of different products.
2. Three-dimensional bronzing
The three-dimensional bronzing technology is a composite technology that combines bronzing technology and concave and convex embossing technology. It uses corrosion or engraving technology to make the graphics of bronzing and embossing into a concave and convex concave plate and a convex concave plate that cooperate with each other to achieve bronzing and The process of embossing technology is completed at one time. This process simultaneously completes bronzing and embossing, which reduces the waste products caused by the inaccurate processing procedures and overprinting, and improves productivity and product quality.
Since the three-dimensional bronzing is a combination of bronzing and concave-convex embossing technology, the resulting product is a three-dimensional pattern in relief, which cannot be printed on. Therefore, the process of first printing and then hot must be used. At the same time, due to its high precision With high quality requirements, it is not suitable for cold stamping technology, but more suitable for hot stamping technology. [next]
Three-dimensional bronzing technology and characteristics
The three-dimensional bronzing technology is very different from ordinary bronzing. In addition to the relief-shaped three-dimensional pattern, it is different in plate making, temperature control and pressure control.
1. Plate making
â‘´Ordinary hot stamping plate
High-quality hot stamping plates are the guarantee of the quality of hot stamping. The production of ordinary hot stamping plates is relatively simple, mainly using photo-etching plate-making process and electronic engraving plate-making process. The commonly used plate material is copper plate or zinc plate. Copperplate is the mainstream hot stamping plate because of its fine texture, smooth surface, good heat transfer performance, wear resistance and pressure resistance, and is not easy to deform. The use of high-quality copperplate can improve the gloss and clarity of hot stamping graphics. Zinc plates can also be used for hot stamping of some packaging printing products with a small number of hot stamping and low quality requirements.
Photo-etching plate making is a traditional manufacturing method with simple process, low cost and low precision. It is mainly suitable for text, thick lines and images with low quality requirements. The hot stamping plate made by electronic engraving can express the image layer richly and finely, and can reproduce fine lines and graphics with uneven thickness, but the relative cost is relatively high.
⑵Three-dimensional hot stamping plate
The production principle of the three-dimensional hot stamping plate is the same as that of the ordinary hot stamping plate, but it is more complicated than the ordinary hot stamping plate, because it needs to form a three-dimensional relief pattern. The printing plate is deeper and the precision is higher. At present, the domestic copper photolithography corrosion method is mainly used. This method has the advantages of low cost and simple process, but it is only suitable for flat bronzing. Due to poor three-dimensional feel, short service life, and printing resistance of only about 100,000 prints, it is commonly used in some packaging that does not require high relief effects Product.
At present, engraved brass plates have been widely used abroad. Scanners are used to scan the patterns to be stamped first, the data is stored in the computer, and then three-dimensional engraving is carried out under the control of the computer and software to form a female gravure with rich three-dimensional patterns. Because it is controlled by a computer, it can form a very fine pattern, which is more ideal for the performance of fine parts, and the printing resistance can reach more than 1 million prints, so it is very suitable for the production of high-quality, large-volume three-dimensional bronzing Yin Die gravure. Of course, due to the need to be equipped with high-end electronic engraving machines, scanners, computers and software, engineering and technical personnel, etc., its production cost is higher than the photo etching method. It is precisely because of its complicated production and technical difficulty that it can better prevent counterfeiting by some illegal manufacturers and has certain anti-counterfeiting functions. Therefore, for some high-quality and long-term work that requires anti-counterfeiting functions, such as cigarette packs, wine bags, health care product packaging and greeting cards, it is very suitable for three-dimensional bronzing. Previously, this hot stamping plate had to be processed abroad, the cost was high, the delivery was not timely, and the design effect was difficult to satisfy. At present, there are a small number of domestic manufacturers that can process this hot stamping plate, which effectively reduces the cost. In particular, the processing manufacturers and designers directly communicate, and can correctly understand the design intent, so as to obtain satisfactory results.
⑶Bottom relief
Three-dimensional bronzing is different from ordinary bronzing. The base of ordinary bronzing is flat and does not require special production. The base of three-dimensional bronzing must be a male relief corresponding to the hot stamping plate, that is, the concave part of the hot stamping plate should be on the base plate. It is raised, and the height of the protrusion corresponds to the depth of the hot stamping plate. The method of making the bottom mold relief is the same as that of the concave-convex embossed positive mold relief, and the commonly used materials are gypsum and glass fiber. If you use gypsum, you must complete the production on the machine, so the process is more complicated, and it is troublesome to replace the bottom plate, but the cost is lower, and it is more commonly used in China. If glass fiber is used, it can be pre-made according to the model of the hot stamping plate, and the positioning hole is made in conjunction with the processed copper plate to facilitate replacement of positioning.
The bottom relief is to cooperate with the hot stamping intaglio to form a three-dimensional relief pattern, which must exactly correspond to the hot stamping plate. However, three-dimensional bronzing is different from concave and convex stamping. Most of the concave and convex stamping does not require heating, and three-dimensional bronzing must be heated at high temperature. During hot stamping, as the temperature rises, the hot stamping plate will expand, but the temperature of the bottom mold relief will remain basically unchanged, which will cause the hot stamping plate and the bottom mold relief to not match, resulting in crushing the bottom mold Or the phenomenon that can not be hot stamped. Therefore, when making the bottom mold relief, the expansion rate of the hot stamping plate must be fully considered to produce an accurate bottom mold relief. [next]
2. Technological requirements for three-dimensional bronzing
Anodized aluminum foil
Anodized aluminum foil is generally composed of 4 to 5 layers of different materials, such as: base film layer (polyester film), peeling layer, colored layer (silver anodized aluminum has no colored layer), aluminized layer, adhesive layer.
The main functions of each layer are:
â‘ The base film layer mainly plays the role of supporting other layers.
â‘¡ The function of the peeling layer is to separate the anodized aluminum foil layer from the base layer, which determines the transferability of the anodized aluminum layer.
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