1. Hot stamping
Hot stamping is to use a certain pressure and temperature to use the template installed on the hot stamping machine to press the printed matter and the hot stamping plate together in a short time, and the metal A process in which foil or colored pigment foil is transferred to the surface of the material to be stamped according to the graphics and text requirements of the stamping template. Since hot stamping is mainly made of gold and silver, it is often called hot stamping. This technology is an important process for increasing the visual effects and class of labels, trademarks, cigarette packages, wine packages and various high-end packaging boxes. In terms of technology, it can be divided into ironing first and then printing and printing first and then ironing. First hot stamping and then printing is to hot stamp an electrochemical aluminum foil layer on a blank substrate first, and then print graphics and text on the surface of the aluminum foil layer. It is mostly used for packaging printed matter that requires large area hot stamping. The printing first and then hot stamping is to hot stamp the required pattern on the printed parts that need to be hot stamped. This is a process that is currently widely used. In terms of hot stamping methods, it can be divided into hot stamping technology and cold stamping technology. Thermal stamping technology is the above-mentioned hot stamping process that requires a certain temperature and pressure to complete the electrochemical aluminum foil transfer. Cold stamping technology is a process in which UV adhesive is applied to the parts of the printed matter that need to be stamped, and the electrochemical aluminum foil is transferred to the surface of the packaged printed matter under a certain pressure. These two methods have their own characteristics and meet the requirements of different products.
2. Three-dimensional hot stamping
Three-dimensional hot stamping technology is a composite technology that combines hot stamping technology and concave and convex embossing technology. It uses corrosion or engraving technology to combine hot stamping and embossed patterns. The paper is made into a female mold gravure plate and a male mold embossing plate that match up and down, realizing the process of hot stamping and embossing embossing in one step. This process completes hot stamping and embossing at the same time, reducing waste products caused by processing procedures and overprinting errors, and improving productivity and product quality.
Since three-dimensional hot stamping is a combination of hot stamping and concave and convex embossing technology, the product effect is a relief-like three-dimensional pattern, which cannot be printed on, so the process of printing first and then hot stamping must be used , and due to its high precision and high quality requirements, it is not suitable for cold stamping technology, but is more suitable for hot stamping technology.
Three-dimensional hot stamping technology and characteristics
Three-dimensional hot stamping technology is very different from ordinary hot stamping. In addition to forming a relief-like three-dimensional pattern, it also has many advantages in plate making, temperature control and pressure control. different.
1. Plate making
⑴Ordinary hot stamping plate
High-quality hot stamping plate is the guarantee of hot stamping quality. The production of ordinary hot stamping plate is relatively simple. , mainly using photographic etching plate making technology and electronic engraving plate making technology. Commonly used plates are copper plates or zinc plates. Copper plates are currently the mainstream hot stamping plates due to their fine texture, smooth surface, good heat transfer performance, wear resistance and pressure resistance, and resistance to deformation. Using high-quality copper plates can improve the gloss and clarity of hot stamping graphics and text. Zinc plates can also be used for hot stamping of some packaging prints with a small number of hot stamps and low quality requirements.
Photographic etching plate making is a traditional production 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 image levels richly and delicately, and can well reproduce fine lines and uneven thickness graphics, but the cost is relatively high.
⑵ Three-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 version because it needs to form a three-dimensional relief pattern. The plates are generally concave and have changes in depth and depth. The depth is deeper than ordinary hot stamping plates and the accuracy is higher. At present, the copper plate photographic etching method is mainly used in China. The advantages of this method are low cost and simple process, but it is only suitable for flat foil stamping. Due to poor three-dimensional effect, short service life, and printing durability of only about 100,000 prints, it is often used in some packaging that does not require high relief effects. on the product.
At present, engraving brass plates has been widely used in foreign countries. The pattern to be hot-stamped is first scanned with a scanner, the data is stored in the computer, and then three-dimensional engraving is performed under the control of the computer and software to form rich layers. Intaglio of female mold with three-dimensional pattern. Because it is controlled by a computer, it can form very fine patterns, and the performance of fine parts is more ideal. The printing endurance can reach more than 1 million prints, so it is very suitable for making three-dimensional hot stamping shadows that require high quality and large printing volume. Mold gravure.
Of course, since it requires high-end electronic engraving machines, scanners, computers and software, engineering and technical personnel, etc., its production cost is higher than that of the photoetching method. Precisely because of its complex production and high technical difficulty, it can better prevent counterfeiting by some unscrupulous manufacturers and has certain anti-counterfeiting functions. Therefore, three-dimensional hot stamping is very suitable for some high-quality long-run jobs that require anti-counterfeiting functions, such as cigarette packages, wine packages, health care product packaging and greeting cards. In the past, this kind of hot stamping plate had to be processed abroad, which was costly, delayed delivery, and the design effect was unsatisfactory. At present, there are a small number of manufacturers in China that can process this kind of hot stamping plate, which effectively reduces costs. Especially when processing manufacturers communicate directly with designers, they can correctly understand the design intent and obtain satisfactory results.
⑶Base relief plate
Three-dimensional hot stamping is different from ordinary hot stamping. The base plate of ordinary hot stamping is flat and does not need to be specially made, while the base plate of three-dimensional hot stamping must be the same as the hot stamping plate. The corresponding male relief plate, that is, the concave part of the hot stamping plate should be convex on the bottom plate, and the height of the bulge corresponds to the concave depth of the hot stamping plate. The method of making the bottom mold relief is the same as the method of making the concave and convex embossing positive relief. Commonly used materials are gypsum and fiberglass. If gypsum is used, it must be made on a machine, so the process is more complicated and it is troublesome to replace the plate. However, the cost is low, and it is now more commonly used in China. If fiberglass is used, it can be pre-made according to the model of the hot stamping plate, and positioning holes can be made with the processed copper plate to facilitate replacement and positioning.
The bottom mold relief plate is used to cooperate with the hot stamping gravure plate to form a three-dimensional relief pattern, and it must accurately correspond to the hot stamping plate. However, three-dimensional hot stamping is different from concave and convex embossing. Most concave and convex embossing does not require heating, while three-dimensional hot stamping requires high-temperature heating. During hot stamping, as the temperature rises, the hot stamping plate will expand, but the temperature of the bottom mold relief plate remains basically unchanged. This will cause the hot stamping plate and the bottom mold relief plate to not match, causing the bottom mold to be crushed. Or cannot be hot stamped. Therefore, when making the bottom mold relief plate, the expansion rate of the hot stamping plate must be fully considered to produce an accurate bottom mold relief plate.
Both hot stamping and embossing technologies are traditional post-press processing technologies and are indispensable processes in packaging and decoration. Now the two are used together, which not only reduces the production process but also improves production efficiency. , the quality, decoration effect and anti-counterfeiting function of product packaging have been greatly improved. Therefore, this technology is now showing strong development momentum. As various conditions mature, it will gradually replace the original process of forming three-dimensional golden patterns by hot stamping and concave and convex embossing. The three-dimensional hot stamping process will become a very promising decoration technology in the field of post-printing packaging and decoration.