Influence of Paper Quality and Molding on Tobacco Package Quality

The fluffing and dusting of cigarette packs during die cutting is a common problem faced by many packaging and printing manufacturers, and there has been no good solution. The following are some of my experiences in years of practice for the benefit of my peers.

The main factors leading to die-fluffing are paper quality and moulding.

Effect of paper quality on die-cutting

As the packaging requirements of some high-end products are becoming higher and higher, the packaging and printing plants generally use white cardboard, coated gold, silver cardboard, and aluminum-plated cardboard when selecting paper. These papers are classified into two types: raw paper and recycled paper; the quality of the original paper is good, the length of paper fibers is longer, and paper hair and paper dust generated during die cutting are less.

The recycled paper has a short paper fiber and easily produces paper dust and paper dust during die cutting. In particular, the reclaimed film gold and silver card paper have a more severe fuzzing because the surface of the PVC film or the PET film brings certain difficulties to die cutting. However, in order to reduce the cost, manufacturers promote the development of environmental protection of paper products and use recycled paper in large quantities. This problem of paper and dust can only be solved by molding.

Molding effects on die-cutting

In general, we take the traditional approach when molding products. When making a die-cut version, it is selected according to the thickness of the paper. For example, when processing O.3mm thick paper, the height of the die cutter is 23.8mm, and the height of the indentation line is 23.8mm-0.3mm=23.5mm. The method used to select the height of the indentation line is correct, but it ignores the distance between the indentation lines on the formed structure of the product. For example, a hard box flip cigarette pack box has a distance of less than 20 mm between the indentation lines. Since the distance is too small, if the indentation is performed at the same time as the die cutting, the indentation will cause the paper to pull and tear the paper when the printed paper has not been completely cut, resulting in the generation of paper. Therefore, to solve the problem of paper hair, we must start from adjusting the distance between the indentation lines so that the printed products can reduce the indentation tension or change the order of the indentation and die-cutting during die-cutting.

The use of steel sandwich die cuts is the best way to solve paper-failure problems. Since die-cut versions are too expensive to be widely accepted, they can be used on indentation lines and die cutters.

Die-cutting knives include straight knife and horizontal knife, and the knife with two different lines has a high and low score on the blade. The lines and heights formed by the blade are directly related to the quality of die-cutting products and the service life of steel knives. The straight knife is better than the horizontal knife in avoiding paper hair; in the service life, the low front knife is much better than the high front knife. Therefore, we must use different types of die cutters for different paper properties when we make the molded version. For example, a ruled high-edge knife is used for die-cutting coated paper jams, and the blade is required to be sharpened. It is best not to use a concave-convex one-shot molding process when processing such products. The main reason is that the indentation pressure and the concave-convex pressure have too great influence on die-cutting and it is difficult to control. In the processing of ordinary cardboard, the use of small front knife, and according to the quality of paper fiber to determine the front of the blade. The straight pattern knife is used when cutting paper with poor or thick paper fibers, and the cross pattern knife is used when the paper fiber is good, which can increase the service life of the knife.

After selecting the die cutter, configure the indentation line. There are many places where the indentation lines of the cigarette pack are in close proximity, such as the hard pack cigarette packs mentioned above. Therefore, when processing these positions, the height of the indentation line cannot be configured as normal, and the pulling force generated on the paper should be minimized during molding to achieve the desired effect. There are two methods: one is to reduce the height of the indentation line; the other is to reduce the thickness of the indentation bottom mold bar. The two can not be used at the same time, otherwise it will not achieve a good indentation effect. The best method is to reduce the height of the indentation line, and the height of the reduction is usually 0.1 to 0.2 mm. According to the thickness of the paper, the specific reduction is determined, the thickness of the paper is reduced by 0.2 mm or more at 350 g/m2 or more, and the paper thickness is reduced by 0 mm or less at 350 g/m2 or less. At the same time, in the position where the indentation line distance is too small, the sponge strip can be pasted to make it play a role of back tension, compress the paper tightly, and reduce the pulling force. In the position of 20mm away from the indentation line, choose the arched rubber strip with Shore hardness of HS75; a bit of the line knife is not suitable for the sponge with excessive hardness, only the breathable sponge plastic with Shore hardness of HS45 is used; If the distance between the positions is less than 5mm, the tape with Shore hardness of HS60 should be used so as to achieve the best effect.

It should be noted here that the above-mentioned die cutters, indentation lines, and sponge glue must be used together to achieve the best results in solving paper-failure problems. Of course, with the continuous development of the packaging and printing industry, packaging and printing materials are also diversifying. The methods described here can only be applied to the currently used coated cardboard and general ordinary cardboard, and not to other special packaging. printing material.