Improve The Bronzing Process Of The Bronzing Machine

Several methods to improve the bronzing process of the automatic bronzing machine

1. Choose the right substrate

There are many substrates that can be bronzed, usually paper, such as: coated paper, white paper, white cardboard, cloth paper, offset paper, etc. But not all paper bronzing effects are ideal. If the surface is rough and the paper is loose, such as book paper, poor offset paper, etc., because the anodized aluminum layer cannot adhere to the surface well, the unique metal The gloss is not well reflected, and it may even fail to be hot-stamped.

 Therefore, the hot stamping substrate should choose paper with dense texture, high smoothness and high surface strength, so as to obtain a good hot stamping effect and fully reflect the unique gloss of anodized aluminum.

2. Choose the appropriate anodized aluminum model according to the different substrates

The structure of anodized aluminum has 5 layers, namely: polyester film layer, peeling layer, color layer (protective layer), aluminum layer and glue layer. There are many types of anodized aluminum, the common ones are No. 1, No. 2, No. 8, No. 12, No. 15 and so on. In addition to gold, there are dozens of colors, such as silver, blue, brown-red, green, and red. Choosing anodized aluminum should not only choose the right color, but also choose the corresponding model according to the different substrates. Different models have different performances and the range of materials suitable for ironing.

Normally, No. 8 is the most used hot stamping for paper products, because No. 8 anodized aluminum has moderate adhesion and good gloss, which is more suitable for hot stamping on general printing paper or glazing paper and varnished cloth. If you are hot stamping on hard plastic, you should choose other corresponding models, such as No. 15 anodized aluminum. The quality of anodized aluminum is mainly checked by visual inspection and hand feeling, such as checking the color, brightness and trachoma of anodized aluminum. Good quality anodized aluminum requires uniform color, smooth and clean after hot stamping, and no trachoma.

The fastness and tightness of anodized aluminum can generally be checked by rubbing it with hands or trying to stick the surface layer with scotch tape. If the anodized aluminum is not easy to fall off, it means that the fastness and tightness are good. It is more suitable for hot stamping small text patterns, and it is not easy to paste the plate during hot stamping; It can be used for hot stamping with relatively sparse graphics and text; in addition, pay attention to the broken ends of anodized aluminum, the less the broken ends, the better.

It is worth noting that the anodized aluminum must be stored properly. It should be stored in a ventilated and dry place. It cannot be mixed with acids, alkalis, alcohols and other substances. It must be protected from moisture, high temperature, and sun. Otherwise, the aluminum will shorten Period of use.

3. Make a good hot stamping plate

Hot stamping plates generally include copper plate, zinc plate and resin plate. Relatively speaking, the copper plate is the best, the zinc plate is moderate, and the resin plate is slightly worse. Therefore, for fine hot stamping, copperplate should be used as much as possible. For the hot stamping plate, it is required to have a smooth surface, clear graphics and text lines, smooth edges, and no pitting and burrs.

If the surface is slightly uneven or slightly scratched or fluffy, wipe it gently with fine charcoal to make it smooth. The corrosion depth of the hot stamping plate should be slightly deeper, at least 0.6mm or more, and the slope should be about 70° to ensure clear hot stamping images and text, reduce the appearance of contiguous and stale plates, and improve the printing resistance rate.

The design of hot stamping text, lines and patterns is very particular. The graphics and texts should be as thick as possible, and the density should be reasonable. If it is too small or too thin, it is easy to miss the strokes; if it is too thick and too dense, it is easy to paste.

4. Control the hot stamping temperature

The hot-stamping temperature has a great influence on the melting degree of the hot-melt silicone resin peeling layer and the adhesive. The hot-stamping temperature must not be lower than the lower limit of the temperature resistance range of the anodized aluminum, which is the minimum temperature to ensure the melting of the anodized aluminum adhesive layer. If the temperature is too low, the melting will not be sufficient, it will cause the hot stamping or the hot stamping is not strong, making the imprints not strong, incomplete, missing pens, broken marks or flowers;

If the temperature is too high, the melting will be excessive, causing the anodized aluminum attached around the print to melt and fall off to produce a paste. At the same time, high temperature will also cause the synthetic resin and dye in the color layer to oxidatively polymerize, resulting in blistering or fogging of the print. The surface of the aluminum layer and the protective layer is oxidized, which reduces the brightness of the hot stamping product or loses its metallic luster

Generally speaking, the electric heating temperature should be adjusted between 80～180℃. For larger hot stamping area, the electric heating temperature is relatively higher; otherwise, it is lower. The specific situation should be determined according to various factors such as the actual temperature of the printing plate, the type of anodized aluminum, the graphics and text conditions, and the most suitable temperature is usually found through trial ironing. The temperature should be the lowest and clear graphics and text lines can be imprinted. As the standard.

5. To reasonably control the stamping pressure

The hot stamping pressure has a great relationship with the adhesion fastness of anodized aluminum. Even if the temperature is right, if the pressure is insufficient, the anodized aluminum will not stick firmly to the substrate, or cause color fading, imprinting, and other phenomena; on the contrary, if the pressure is too high, the compression deformation of the liner and the substrate will be too large, resulting in paste The plate or print becomes thicker. Therefore, the hot stamping pressure should be adjusted carefully.

When setting the stamping pressure, the main considerations should be: the properties of anodized aluminum, stamping temperature, stamping speed, substrate, etc. Generally speaking, the paper is strong, smooth, the ink layer printed is thick, and the hot stamping temperature is high and the speed of the car is slow, the stamping pressure should be lower; on the contrary, it should be higher.

In addition, similar to printing, you should also pay attention to the hot stamping liner. For smooth paper, such as: coated paper, glass cardboard, it is best to use hard liner paper, so that the impression obtained is clearer; on the contrary, for smoothness For poor, rough paper, the liner should be softer, especially when the hot stamping area is large.

Finally, the hot stamping pressure must be even. If it is found that the hot stamping cannot be performed locally or tingling occurs during the trial printing, it may be because the pressure here is not flat. You can pad thin paper on the flat plate there and make appropriate adjustments.

6. The hot stamping speed is as constant as possible

The contact time is proportional to the hot stamping fastness under certain conditions, and the hot stamping speed determines the contact time between the anodized aluminum and the substrate. The hot stamping speed is slow, and the contact time between the anodized aluminum and the substrate is long, and the bonding is relatively strong, which is conducive to hot stamping; on the contrary, the hot stamping speed is fast, the hot stamping contact time is short, and the hot-melt silicone resin layer and adhesive of the anodized aluminum If it has not been completely melted, it will cause the hot stamping to fail or the imprint to be blurred.

Of course, the hot stamping speed must also be compatible with the pressure and temperature. If the hot stamping speed increases, the temperature and pressure should also be increased appropriately. In addition, the performance of the anodized aluminum itself has a greater impact on the hot stamping speed. High-quality anodized aluminum can achieve fast hot stamping, which is quite different from imported anodized aluminum.

Domestic anodized aluminum is usually only suitable for low-speed hot stamping, the speed is about 2000 sheets/h, and the highest is generally not more than 3000 sheets/h; imported ones can reach 8000 sheets/h, or even higher. Regardless of the speed, the important point is: the hot stamping speed should be kept as relatively stable as possible, and should not be changed easily.

Under the premise of stable hot stamping speed, the hot stamping temperature and pressure should be adjusted appropriately to optimize the hot stamping effect, which can reduce the variable factors, make the operation stable, and easily control the hot stamping quality.