You know the technical key to flexo inks, but what about the cost control method? Today, Xiaobian teaches you how to control the cost of flexo inks.

Different types of inks combined

Flexo inks generally include three types of water-based inks, UV inks, and solvent-based inks. However, if the three flexo inks can be used differently or in combination, it will achieve a win-win situation in printing effect and cost control.

Case: The printing process of a cigarette pack soft box is "large area red + spot color text + glazing". Large-area red uses alcohol-soluble ink (solvent type) due to the large amount of ink used. Compared with water-based ink, its advantages are not only in the price, but also avoid the ink layer produced by the water-based ink due to the infiltration of the adhesive. Reconstitution and resulting discoloration problems. Spot color text is printed using water-based inks. The glazing uses UV varnish, which has higher protection and gloss than aqueous varnish.

According to statistics, the average area of self-adhesive labels and graphics currently accounts for only about 30% of the printed perimeter. Estimate the amount of ink as follows:

Printing volume: 200,000 pieces;

Label size: 120mm × 60mm;

Printing color: 6 colors;

The average amount of ink used: 240g;

Actual use (the waste of ink tray and other factors): about 300g.

However, if large-area color blocks are printed, the use of water-based inks can save costs. Taking the above label order as an example, if the area of a certain color image accounts for 80% of the entire label area, and the BCM value of the anilox roller is 5.0, the ink usage is 3.3 kg (see the flexo ink consumption for the specific calculation method). How to accurately predict? Calculate it for you!). According to the actual measurement, 1kg of water-based ink will be used in about 20 to 30 minutes.

Under such a large amount of ink usage, the ammonia in the aqueous ink is too late to be volatilized, the aqueous ink has already been used, and at the same time, new ink is added to the ink tray. Therefore, the pH of the color aqueous ink is quite stable, and it does not require much effort to control when printing, and there is not much difference from the use of UV ink. But compared to UV inks, you can save a lot of cost. Other inks that use less can still use UV inks. In this way, both cost and printing effects can be taken into account.

Matching adhesion

The adhesion of the aqueous ink to the film-like material and the adhesion when the UV ink is overprinted with each other are formulated. First, you need to choose a suitable water-based ink to make it adhere well to the surface of the film-based material. Secondly, pay attention to whether the water-based ink material or varnish can be overprinted with UV ink. If it cannot be overprinted or overprinted, UV If the adhesion of the ink is not good, it is necessary to consider printing a special coating between the two to ensure the quality of the overprint. Otherwise, the ink of the UV ink printed on the surface of the aqueous ink will not pass the 3M tape test.

Control the relationship between ink pressure and printing pressure

If UV ink is used for printing, the printing pressure is slightly larger, which has little effect on the quality of the label. However, if water-based ink is used for printing, the printing pressure is too large, and the edge of the image is likely to produce "wild ink", which causes problems such as dirt and burrs. If it leads to unnecessary waste, it will not be worth the loss.

Consider the cost from the product process

Note the difference between two-layer ink printing and one layer ink printing

Usually, in large-area field printing, most label printing companies use two layers of ink to avoid the occurrence of dirty spots. In fact, there is another reason for doing this: in the case of the same color density, the two layers of thin ink are used less than a layer of thick ink.

Case: A job requires a 500 line/inch, 4.0 BCM anilox roll to print Kodak red. In order to reduce the dirty spots when the ink is printed on the foamed PS material, a two-layer ink printing method is employed.

It should be noted that when printing a thicker layer of ink, the flatness of the ink is usually not so good, it is easy to bloom, not real, and the color looks slightly lighter. If printing on coated paper, the penetration of the ink will aggravate this phenomenon; however, when printing two layers of ink, the situation is different. The first layer of ink is usually printed thinner, except that it can be taken away on the substrate. In addition to the dirty spots, it can also fill the gaps or unevenness on the surface of the printing material. After printing the second layer of ink, the printing effect in the field will be more flat, and the density value measured by the instrument will be higher.

Determine if you need to glaze

Glazing has two purposes: one is to increase the gloss of the label, and the other is to protect the label from wear. If it is just to increase the gloss, the flexo ink itself has a certain brightness, so there is no need to polish it. If it is to protect the label, some labels have no possibility of wear and tear during transportation and use, and do not need to be glazed. If you do not consider the actual situation, you will choose the glazing process blindly, which will lead to unnecessary varnish loss. Although varnish is cheaper than ordinary inks, varnish is often full-coated and has a thick coating, so it is used in large quantities and wastes.

Therefore, it is necessary to consider the design of the previous process, such as whether it is necessary to glaze, or whether it needs a full version of glazing. If the position where the label is attached does not rub at all during labeling, transportation, and use, then the ultra-transparent label may not be glazed. If it is a special-shaped label, because it needs a large area of die-cutting, then there is no need to full-plate glazing, only partial glazing is required. For the part that needs to be glazed, the thickness of the varnish layer should also be considered to meet the customer's requirements. For labels with wear resistance requirements, it is necessary to ensure sufficient varnish thickness, and sometimes even some anti-wear additives need to be added to the varnish. In short, to meet the needs of customers, do not need super quality, super cost, increase unnecessary processes will result in waste of resources.

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