The cracking line refers to the cracking of the paper at the indentation when the corrugated cardboard is die-cut by a flexo printing die-cutting machine or when a corrugated box product is folded. This is a common problem in die-cutting, especially in dry weather. It should be analyzed on a case-by-case basis:
1. Corrugated cardboard is brittle and has low water content, especially the paper that has been polished at high temperature, and it is easy to burst when die-cutting. At this time, adjust the humidity of the paper before die-cutting, use a water machine to make the paper difficult to pass water, increase its water content, make the grade slightly more flexible, and then put it on the die-cutting machine. After die-cutting, if the thread bursts when pasting the box, you can wipe water on the crease to reduce the bursting state.
2. The surface of the printed corrugated box has a large area of blue or black and other dark color solids, and it is easy to burst colors and lines after die-cutting. When printing, no or less ink additives are added to the dark ink to enhance the adhesion of the ink on the paper and reduce the appearance of bursting colors and lines.
3. When the thickness of the corrugated cardboard is too large, it is easy to break the line. At this time, the height of the die-cut steel line should be selected reasonably.
4. The paper under the steel plate is prone to explosion. At this moment, the paper should be thinned.
5. When the pressure of the die-cutting machine is too high, it is easy to explode. At this moment, the pressure should be reduced to make the waste edges just separate.
6. The indentation die or bottom touch paper is too thick, the indentation is narrow, and the line is explosive. The indentation die with appropriate thickness should be selected, and the indentation width should be moderate.
7. Cut off the explosive wire where the fallen paper powder accumulates in the groove. The operator should eradicate clean paper dust and foreign matter in time.
