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Quality Problems and Their Solutions For Paper Box Packaging

custom paper box packaging (2).jpgDie cutting is the key step in the process of paper box packaging.

Do you know how to solve the eight problems of paper box packaging die cutting? How to ensure the quality of die cutting is a very concerned problem in printing factory. At present, the main problems faced by the paper box packaging printing factory are long plate change time, poor printing to cutting accuracy, poor die-cutting quality, too many paper hairs, too many connection points, irregular trace lines, slow production speed and high scrap rate.

Following are some common quality problems and their solutions for paper box packaging, hoping to be helpful.

Here are some common quality problems and their solutions for paper box packaging, hoping to be helpful.

1. Die cutting accuracy is not high to the paper box packaging

Cause of problem: the reason of low die-cutting accuracy is the problem of die-cutting version body, as well as the problem of printing. The error of the die-cutting plate made by hand is large; the different working environment of the die-cutting indentation and the printing process will cause the paper deformation, resulting in the inaccurate position of the die-cutting indentation, especially after polishing and laminating, the paper deformation is more serious, affecting the die-cutting accuracy.

Solution for paper box packaging: Select advanced die-cutting plate making technology to improve the accuracy of die-cutting plate. Try to ensure that the die-cutting indentation and printing process are carried out in the same working environment, or that the working environment is the same (i.e. the same temperature, relative humidity, etc.); carry out die-cutting pretreatment for the paper after polishing and laminating to minimize the impact of paper deformation on die-cutting accuracy.


2. Die cutting indentation produces "broken line" and "dark line" of paper box packaging

Cause of the problem: "burst line" refers to the breaking or partial breaking of the paper fiber due to the excessive pressure of the die-cutting indentation, which exceeds the bearing limit of the paper fiber; "dark line" refers to the unnecessary indentation line, which is generally due to the improper selection of die-cutting plate and indentation steel line, improper adjustment of die-cutting pressure, poor quality of paper, inconsistent direction of paper fiber and die-cutting plate cutter arrangement, and paper It is caused by the low tensile water content and the decrease of flexibility.

Solution for paper box packaging: Select the appropriate die-cutting plate; adjust the die-cutting pressure properly; put the printed matter to be die-cut in the workshop for a period of time before die-cutting; improve the relative humidity of the workshop environment.

In addition, there is a special case, that is, when die-cutting the small paper box packaging of cigarette pack in the hard box, because the distance between the indentation lines in many positions is very close, if the height of the indentation steel line is configured according to the normal situation, the tensile force on the paper is too large when die-pressing, which will also cause the "burst line".

Therefore, we should try to minimize the tensile force on paper. There are two methods: one is to reduce the height of the indentation steel wire; the other is to reduce the thickness of the bottom die strip of the indentation, but the two cannot be used at the same time, otherwise it will not have a good indentation effect. The better method is to reduce the height of the indentation steel wire, which is usually 0.1-0.2mm, which should be determined quantitatively according to the paper. The height of the indentation steel wire that needs to be reduced for the paper with the ration above 350g / m2 is 0.2mm, and the paper with the ration below 350g / m2 should be reduced by 0.1mm.


3. The indentation line is not full

Cause of the problem: under the action of die-cutting pressure, the indentation steel wire will twist, which will cause the indentation line to move; if the die-cutting pressure is insufficient, the indentation line will not be full.

Solution for paper box packaging:The problem can be improved by changing the die-cutting plate and increasing the die-cutting pressure.


4. Fluffing and dusting during die cutting for paper box packaging

Cause of the problem: in die-cutting, often die-cutting products of paper box packaging edge is not smooth, fluffing phenomenon, especially from the indentation line near some of the edge is more serious. This is due to the die-cutting press, the die-cutting plate on the rubber strip, indentation steel wire on the paper produced tension, paper was not completely cut through when the tension was produced, there was a burr.

Solution for paper box packaging: First of all, different types of die cutters should be selected according to the paper. Die cutting knife includes straight line knife and cross line knife. There are two kinds of blade with high and short lines. The different lines and high and short lines formed by the blade are directly related to the quality of die cutting and the service life of die cutting knife. The straight blade is better than the cross blade in avoiding the fluffing of die cutting, and the short blade is better than the high blade in service life. In the process of die-cutting laminating paperboard, straight grain high blade knife should be selected, and the blade is required to be grind. It is better not to use the one-time forming process of pressing concave convex, otherwise the pressure will have a great impact on die-cutting; while in the process of ordinary paperboard, short blade knife should be selected, and the grain of blade should be determined according to the quality of paper fiber. For the paper with poor or thick fiber, straight grain knife should be selected. For the paper with good fiber quality, cross grain knife can be selected to improve the service life of die cutter.

Secondly, we can also paste a 60 arch rubber strip on the die-cutting knife near the indentation steel wire to reduce the tension of the indentation steel wire on the paper when the die-cutting is combined and pressed. For example, 0.4mm x 1.3mm and 23.4mm high indented steel wire is usually used when cutting 300gsm paper. In case of this fault, 0.4mm x 1.2mm and 23.3mm high sharp indented steel wire can be used instead. In this way, the tensile force on paper during die cutting and pressing can be reduced, and the problem of die cutting fluffing can be basically solved.


5. Die cutting "paste" of paper box packaging

Problem cause: die cutting "paste" refers to the paper adhesion on the die-cutting plate, the causes of this failure are as follows. The density or hardness of the sponge adhesive strip pasted around the die-cutting knife is too small, and the resilience is insufficient; the cutting edge of the die-cutting knife is not sharp, and the paper is too thick, which causes the knife sticking when clamping or die-cutting.

Solution for paper box packaging: According to the distribution of die-cutting knife, choose sponge strips with different hardness reasonably or replace the die-cutting knife.


6. Die cutting "bulk"

Reason for the problem: die cutting "bulk plate" is mainly related to the plate making process and sponge rubber strip. If the shape of the movable parts is complex or there are many arranged movable parts, and the connecting points on the die-cutting plate are small and few, it is easy to cause die-cutting time scattering.

Solution for paper box packaging: Properly increase the number of connecting points on the die-cutting plate, and try to keep the length direction of printed matter consistent with the paper feeding direction when making the die-cutting plate.


7. Too many connection points

End users of paper box packaging always require smaller connection points, and manufacturers always make the machine run faster, which increases the difficulty of operators. In order to reduce the difficulty, the connection point should be made at the stress point with a wire grinding machine, and a hard rubber strip or cork should be used at the knife edge where the connection point needs to be made to prevent the connection point from breaking, so that the connection point can be smaller and fewer.


8. Irregular trace

Considering the need of folding paste paper box packaging, the color box must have good indentation line. What's more, when these boxes are running on the automatic packaging machine, the opening force must be stable and consistent. In this way, it is the basic element to select the appropriate type of marking line when die cutting. According to the thickness of the paper, choose the height and width of the marking line, and stick the appropriate marking line on the die-cutting bottom plate, the indentation can achieve higher quality and make the paper box packaging easy to fold.