Electro-aluminum foil stamping process principle

Aluminium hot stamping is a very important post-printing process in packaging and printing. It is mainly a hot stamping pattern. Text. Lines to highlight the product's name, trademark. Ang licensing, landscaping products, thereby improving the quality of packaging products. Anodized aluminum stamping is also often used to hardcover book covers and greeting cards. Calendar and other products after the printing process.

The structure of anodized aluminum is shown in the figure below. The hot stamping process is as follows: The aluminum foil is heated by the hot stamping plate, the peeling layer is melted, and then the adhesive layer is also melted. When the adhesive layer is adhered to the substrate during printing, the colored layer is The base sheet of the polyester sheet is detached, and the aluminized layer and the colored layer remain on the substrate.

The stamping of electro-aluminum on the packaging can not only play a role in beautifying the product and improving the grade of the product, but also play a certain anti-counterfeiting effect.

Stamping after printing

One of the purposes of increasing the hot stamping process is to improve the product quality. However, in practical applications, only reasonable use can play a multiplier role. Conversely, not only does it fail to show the advantages of the product, but it also causes waste. The following points should be taken into account when using the electro-aluminum hot stamping process.

1. Product Design Considerations

1 should fully consider the hot stamping parts, that is, the matching of the color and the printing color of the hot stamping characters or patterns, and the effect of the hot stamping process on the hot stamping.

2 Consider the overall effect of hot stamping and the cost of hot stamping. For example, some products often only hot stamp the outline and text of the pattern, and do not directly stamp the pattern to achieve the effect of point lining; for certain aluminum-plated paper cigarette packs, the printing design can be achieved by first printing the transparent yellow and pressing the bumps. Replace hot stamping to reduce costs.

3 Hot stamping on a large area should also take into account the hot stamping site and the printing pattern of the paper, which need to be based on product overlay accuracy, generally set to 0.2-0.5mm. Of course, it is necessary to take into consideration the stamping adaptability of the aluminum foil itself.

2. The effect of printing before hot and after hot processing

General hot stamping products must be printed before hot stamping, with monochrome printing and multi-color printing; stamping after embossing, UV glazing, laminating, and then printing, die-cutting, paste boxes and other processing.

Pre-hot printing should pay attention to the following points: dark thin printing, the use of strong coloring ink, in the ink as little as possible to add anti-adhesive agent and retreat agent, try not to spray, printing ink, coating oil and anodized aluminum The matching of printability of hot stamping should also prevent the influence of ink crystallization on hot stamping.

After pressing, it is pressed and embossed and die-cut. The effect of the gluing box on the hot stamping is not great. Just take care to prevent the hot stamping foil from being scratched. If you want to use uV varnish after hot stamping, you should consider the acceptability of the electro-aluminum, that is, the surface tension of the electro-aluminum is greater than the surface tension of the UV varnish. If allowed:, the hot stamping part of some products can be hollowed out. If UV inks are first printed and then hot stamped according to the process requirements, the stamping properties of the UV varnish should be checked first. Generally, the dyne pen is used to test the UV light film layer, and the surface tension can be more than 3.810-2N/m. Electrochemical aluminum hot stamping.

3. Selection of hot stamping materials and equipment

Hot stamping materials and hot stamping equipment are the two most critical factors affecting the stamping effect.

1 hot stamping material

Hot stamping material is anodized aluminum. There are many kinds of galvanized aluminum on the market today, including ceramic anodized aluminum and paper anodized aluminum. Glass electro-aluminum, etc.; complex grades, both domestic aluminum, real estate in Shanghai, Zhejiang, Fujian, and the United States. Japan-made, German-made imported aluminum, and their respective advantages and disadvantages. Here we mainly discuss paper aluminum.
The hot stamping adaptability of anodized aluminum includes surface finish, brightness, sharpness, hot stamping adaptability to graphic and small texts, surface flying gold and flash edge problems, etc., depending on the level of printed materials, packaging products, and anodized aluminum. The choice of price and hot stamping trade-offs.

2 hot stamping equipment

Hot stamping equipment is widely used in China is a hand-type hot stamping machine, the main hot stamping requirements are not very high packaging products. It has low cost. Small footprint, easy operation, strong hot stamping advantages, but the hot stamping of high precision products, the error is larger, higher reject rate. If you have a hot box, most printing companies in China choose Bobst Hot Stamping Machine. The hot stamping accuracy is very high, and the control of hot stamping temperature, pressure and speed is better than other hot stamping machines. At present, some domestic hot stamping machines are also highly accurate and the price is much lower than that of imported high-end equipment.

Hot printing

After printing, hot stamping is a top technology that is used in cigarette pack printing. Its stereoscopic effect is beyond the reach of other technologies. After the hot printing, the large area laser electro-aluminum is generally stamped on the spot color ink, and then the UV ink is printed on the electro-aluminum. Its printing materials. Printing inks, printing equipment, and printers are highly demanding. The following points should be noted in this process:

1 Select an electro-aluminum with a surface tension of (4.0-4.6) X10-2N/m to ensure that the ink has good adhesion.

2 In the hot stamping process, it should be noted that hot stamping does not allow paste version. Anti-pull, hot stamping is not on the phenomenon. Otherwise, the galvanized aluminum stamped on the second printing will fall off and accumulate on the blanket, seriously affecting product quality and production efficiency.

3 comprehensive consideration of printing, hot stamping, hot printing between the three appropriate control shop environment temperature, humidity, try to avoid human factors caused by the report

4 When designing, it should be noted whether it is possible to hollow out or separate hot stamping in a large area of ​​hot stamping to reduce the difficulty of hot stamping.

Stamping security

With the development of society, people are paying more and more attention to the security of high-end products. Anti-counterfeiting is almost applied to the entire packaging industry, such as ink security, printing pattern security, paper security, hot stamping security, UV oil security and so on. Hot stamping and anti-counterfeiting are relatively demanding. Control a more sophisticated anti-counterfeiting technology, here mainly introduces two anti-counterfeiting methods.

(1) The laser pattern of aluminum foil itself is used to transfer the hot stamping pattern to the substrate, so that the surface of the substrate can be stamped with various rainbow patterns to achieve anti-counterfeiting. This type of electrochemical aluminum technology is more advanced, more difficult to produce, and more expensive, so that imitation of those who deter.

2 Using holographic anti-counterfeiting patterns on anodized aluminum, the complete pattern is positioned on the substrate-fixed pattern by mechanical control. This process uses hot stamping. The holographic anti-counterfeiting anodized aluminum pattern and the substrate pattern are in alignment and register, making it more difficult.

As hot stamping and anti-counterfeiting is a relatively new technology: higher requirements are imposed on operators, and they must be reasonably controlled to minimize unnecessary waste.


Source: Zhejiang Hengfeng Packaging Co., Ltd.