Foil stamping Suitability

The so-called Foil stamping suitability refers to the model selection of electrochemical aluminum and the matching among stamping speed, temperature, printing 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 Foil stamping quality.

1. Poor hot stamping or false hot stamping: This is related to the surface characteristics of the printed piece, the properties of electrochemical aluminum, hot stamping temperature, printing pressure and other factors.

① Too much powder is sprayed on the surface of the printed piece 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.

② Improper selection of electrochemical aluminum will directly affect the fastness of bronzing. According to the size of the bronzing area and the characteristics of the materials to be bronzed, we should comprehensively consider what type of anodized aluminum should be selected.

③ Failure to correctly master the bronzing equipment and the matching between the pressing time and the hot stamping temperature will affect the hot stamping fastness and the clarity of the picture and text outline. Due to different equipment and materials to be hot stamped, the hot stamping time and hot stamping temperature are different.

For example, the high-speed round press is fast, and the hot stamping temperature will be higher than that of round flattening or flat flattening when the imprinting line (NIP) contacts. Generally, the temperature of round pressing and hot stamping is 190 ℃ ~ 220 ℃, the temperature of round flattening is about 130 ℃ ~ 150 ℃, and the temperature of flat flattening is about 100 ℃ ~ 120 ℃. Of course, the hot pressing time, hot stamping temperature and production efficiency are also restricted by the transfer performance of anodized to a large extent.

2. Reverse pulling: reverse pulling refers to the pulling away of printing ink or varnish on printed parts by anodized aluminum after hot stamping. This is mainly because the ink on the surface of printed matter is not dry or the UV and other post-processing treatments on the surface of printed matter are improper, resulting in the poor combination of the ink and UV oil on the surface of printed matter with the paper surface. Solution: to be printed matter (printed matter) drying and then foil stamping. In addition, electrochemical aluminum with low separation force and excellent heat transfer property can be selected.

3. Filling in and Anodized Discoloration After Hot stamping: filling in is mainly caused by poor production of hot stamping plate, loose installation of anodized plate or incorrect foil feeding of anodized plate. The color change of anodized after hot stamping is mainly caused by too high hot stamping temperature. In addition, anodized wrinkling is also easy to cause uneven hot stamping and color change, 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 foil stamping plate and scorching before hot stamping.

4. Improper Process Arrangement Destroys the surface gloss of anodized aluminum, and the image and text outline is weak: for foil stamping 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 destroy the surface gloss of anodized aluminum, so it is not suitable to use water-soluble glue for film covering, otherwise the surface of anodized aluminum will be blackened, and it is very easy to cause the gold powder to stick to the edge of the image and text, resulting in virtual phenomenon. ② After Foil stamping, due to the effect of printing pressure and the fact that the glue is not easy to penetrate the surface of anodized aluminum, it is easy to cause the separation of OPP and paper at the bronzing position and affect the product quality. The correct process is to cover the film before Foil stamping, and select the anodized aluminum matching opp.