How to effectively solve the problem of corner and burst during the processing of color boxes corrugated paper box

The problem of corner and burst during the die-cutting, bonding mailer shipping box, and packaging process of color boxes often troubles many packaging and printing enterprises. Next, let’s take a look at the handling methods of senior technical personnel for such problems.

1. Improper pressure leading to bursting 

1.1 There are foreign objects in the indentation groove of the bottom plate, causing a sharp increase in pressure during die-cutting. This is a common and destructive cause of bursting in production. It can cause the entire dark line to break, leading to product scrapping. paper gift box

1.2 Runout, which means that the die-cut or bottom plate is positioned so that the steel wire falls on the outside of the indentation groove. The burst caused by this reason is mainly concentrated on the dark lines in the same direction, which is due to the lack of tight fit between the cutting or indentation knife and the wooden template, resulting in deviation under pressure.drawer-box

The selection of steel wire thickness and indentation groove width does not match the paper material. According to the requirements of the die-cutting process, different steel wires should be used for different types of paper, as well as different thicknesses of base plates and different widths of hidden lines. If not matched, it is easy to cause hidden lines to burst.

2. Cracking caused by die-cutting plate production process

2.1 Improper handling of the steel wire position or burrs left when cutting the steel wire during the production of the die cutting plate. If the product has undergone surface treatment in die cutting, such as lamination. Burrs left on the steel wire during die cutting can damage the tensile strength of the surface film, and the film cannot withstand force during product molding, leading to cracking.

2.2 The steel knife and wire at the dark line have a blade and interface. Due to the unevenness of the interface, tearing may occur during die cutting.

When the sponge pad of the wire pressing knife is not in the appropriate position, the wire pressing will burst, and the deformation and damage of the wire pressing knife can also cause the wire pressing to burst.

Is the combination of the knife and wire on the knife mold reasonable. Especially when the design did not consider the thickness of the paper, the overlap between the knife and the line cannot be effectively avoided, and interference occurs during molding, resulting in excessive concentration of force at this point and the occurrence of cracking.

3. Material quality issues

3.1 If the water content of the paper is too low, the paper becomes brittle. This phenomenon often occurs in winter, as the weather is dry and cold, and the relative humidity in the air is low, which directly affects the moisture content of the cardboard, causing the cardboard to break after pressing. Generally, the moisture content of the base paper is controlled within the upper limit (between 8% -14%);

3.2 Paper lamination material: Biaxially stretched polypropylene film has slight gaps, resulting in a decrease in tensile strength. Lamination is a common surface treatment method for paper, mainly made of BOPP film. If the BOPP film is damaged before die-cutting, it will cause the BOPP film to be unable to withstand force and burst when bent after die-cutting. The bursting of the film only occurs in the film layer, and as the force point increases, it will extend along the bursting direction. The bottom layer of paper does not burst, indicating that it is not related to the paper. If the film is not broken and the paper has already burst, it is not related to the film and there is a problem with the paper.

3.3 Paper orientation is incorrect. When die-cutting, if the direction of the indentation steel wire is perpendicular to the direction of the paper fibers, which will cause radial damage to the paper fibers, the dark lines are prone to bending, forming well, and the angle is small; If the indented steel wire is parallel to the fiber direction of the paper and the paper is not damaged horizontally, the dark wire is not easily bent and formed into a rounded corner with a large angle, which has a strong support force on the outer layer of the paper and is prone to cracking. The directionality of paper has little impact on the die-cutting of single sheet paper products, but it is not easy to burst lines due to poor molding. However, it has a significant impact on card mounted products. If not handled properly, not only is the molding not good, but it is also easy to burst lines. The main reason is that the dark lines parallel to the paper grain burst lines in different positions, while the other direction does not.

3.4 Corrugation configuration is too high. The bursting strength and transverse ring compression strength of the base paper are one of the influencing factors. If the folding resistance of the inner paper is too low, it can also easily cause bursting.

3.5 The mold has been used for too long. After prolonged use of the die-cutting plate in die-cutting, the wire pressing knife may become loose, causing the wire pressing knife to bounce during the die-cutting process, causing the cardboard wire pressing to burst. Due to the prolonged use of the rubber pad, the uneven height of the pad caused the pressure line to burst.