Views:70 Author:Site Editor Publish Time: 2021-07-20 Origin:Site
When the steel wire of the creasing die is pressed into the groove, the cardboard is subjected to three kinds of forces: pressure, tension and surface tension. These three forces not only cause permanent deformation of the cardboard, but also reduce the cohesion between the fibers of the cardboard layers.
When the paper is folded, the surface of the paper is under tension and the inner layer is under pressure. If the pressure exceeds the cohesive force between the paper fibers, the internal fibers of the cardboard will break, and the paper will become soft and flexible at the fold. But the pressure shouldn't be too big, the outside monster will break when the cardboard tension is exceeded. During the die-cutting process, the surface tension of the cardboard will increase as the number of impressions on the cardboard increases. Burst line refers to the paper cracking at the indentation when the product is die-cut or the finished product is folded. This is a problem that often occurs in indentation, especially in dry weather. Specific analysis should be based on specific conditions:
1. The paper is brittle and has low water content, especially the high-temperature polished paper, which is easy to explode during die cutting.
At this time, adjust the humidity of the paper before die-cutting, and use a water-passing machine to pass water to the back of the paper to increase its moisture content and make it slightly flexible, and then go to the die-cutting machine. After die-cutting, if the line bursts when pasting the box, wipe water at the crease to relieve the line burst.
2. There is a large area of deep blue or black on the surface of the printed matter, which is easy to explode after die cutting. No or less ink additives are added to the dark ink during printing to strengthen the adhesion of the ink on the paper and reduce color bursting and line bursting.
3. When the paper thickness is too large, it is easy to produce burst lines. At this time, the height of the die-cutting steel line should be selected reasonably.
4. It is easy to cause explosion line after the steel plate is filled with paper. At this time, the paper should be thinned.
5. Excessive pressure on the die-cutting machine may cause the line to burst. At this time, the pressure should be reduced to make the waste edges just separate.
6. The indentation die or bottom paper is too thick and the indentation is narrow, which may cause line burst. An indentation die of appropriate thickness should be selected, and the indentation width should be moderate.
7. The paper dust falling from the incision accumulates in the groove, which may cause burst lines. The operator should promptly remove clean paper, foreign matter, etc.