A variety of techniques for flexo printing techniques

Flexo printing has numerous connection technologies such as screen printing, embossing, and die cutting, and integrating each process into a flexo connection is a process of meeting challenges. The “84mm Longfeng Chingxiang” cigarette packet printed by Jingjia Company in the previous year contained a special process effect—embossing. Friends who are engaged in flexo printing all know that the quality of the stickers is good and bad, they are oblique, and they have a great impact on the quality of the products. Not only are the printing plates, but the bump version is more complicated.

At the end of 2004, a new single “84mm Longfeng Chengxiang soft pack box” was transferred from offset printing. This is a new process for flexo printing, but why did it go to flexo printing? Is offset printing impossible? No, because offset printing is a single printing, the products often need to go offline to the next process. After printing to the finished product, two post-processes are required. This is exactly the case for "84mm Longfeng Chengxiang". Each subsequent process has intangible damage and will result in greater waste. The feature of flexo printing is the process of molding from the material to the finished product.

Flexo printing is a circular press printing principle, embossing is divided into intaglio and relief printing, gravure is a pattern module made of copper, set on the metal roller. The letterpress is divided into two parts, the metal roller and the resin plate. It is necessary to attach the resin plate to the position corresponding to each gravure plate. It is very difficult to attach them to the plate. The relief lines are relatively small and can easily be crushed. Therefore, the supplier has made two positioning holes on the embossed plate when making the plate. The plate is fixed in the same position with two positioning pins. Reliance on double-sided adhesive to attach the resin plate to the light roller is complete. At the time of sticking, there were many intaglio and relief positioning holes that were not in the same position. The best solution was to move the letter out of position so that it would be able to align with the intaglio, and thus barely put a set of stickers. If there are no two hours after the start of the operation, there are many patterns that are not clear. Stop and see, the original is the Toppan crushed. Because the pattern is relatively small, if it is inaccurate, it is very easy to press off the grain and you need to change the relief.

In combination with the bump version, it is necessary to think about how to better, faster and more accurate to stick the Toppan. First stick the double-sided adhesive on the resin plate, and then cut off the back of the double-layered adhesive on the back of the layered paper, and leave it in front of it so that even if the plate is stuck on the roller, it will not be stuck. Shake. Then, align the text on the letterpress with the text on the intaglio, gently press the letterpress on the intaglio plate, and turn the platen roller so that they turn to the position where the force is applied at the same time. The handle is removed and the appropriate pressure is added. Then, remove all the off-layer papers that have not been removed, and attach the entire version to the metal roller. The entire version is even better. If this is not done, look at what it is like, for example, if the letterpress is too low and you need to move up a bit, then lift up the version from below, bend it upwards, and grasp the balance. Attach it to the roller. Then lift the plate from above and lift it to the position where it was bent just below. Pull it slightly upwards and gently press it against the roller. This should be fine. In the second production, according to this method, there was no crushed condition, but there was a new problem: the double-sided adhesive was not pressure-resistant, and the double-sided adhesive under the letterpress was opened for several hours. It is crushed, so the lines will not be clear. The first thing I think of is to use white cardboard instead. First remove the double-sided tape under the pattern, and then cut the white cardboard into the shape of the double-sided tape. Stick the white cardboard in that place with glue. Just paste it as you did just now.

After the sticker is solved, simply talk about pressure and non-uniformity. There are three possible reasons. First, the pressure of the base itself is not evenly adjusted. When the manual pressure is applied, the strength of the two sides is not the same. Uneven pressure. At this time, you can loosen all the pressure on both sides, grasp the strength, while adding until the appropriate; second, when the white pad paper, may choose the white cardboard thickness is not the same, you should consider changing the white cardboard; Third, the resin version may have quality problems. When the materials are inspected, sometimes the quality of the plate cannot be recognized by the naked eye, but if you touch it with the experience of a sticker, you can feel it. If the pressure is light after you paste the good version, Depending on the size of the pressure, a suitable thickness of the tape can be applied to the surface of the resin plate. The light pressure is not light. But if the pressure is heavy, then choose another version.

Source: Packaging Expo