Process technology of making tin boxes and paper boxes
With the development of society and the continuous improvement of people's living standards, consumers not only require the intrinsic quality of the goods, but also put forward higher requirements for the packaging of the goods when purchasing goods. This includes not only the requirements for commodity packaging and decoration design, but also the requirements for packaging post-press processing quality. The part of the printed material is compacted to produce traces and make it have a certain unevenness in the space called indentation.
Indentation processing technology was initially only used for the molding of paper packaging boxes, and then gradually applied to the surface processing of various printed matter, especially the surface finishing processing of relatively high-end paper boxes, cartons, trademarks, and artworks. Now, indentation technology is one of the important means to realize packaging design. It not only plays an important role in the final quality and effect of packaging, but also improves the artistic effect of printed matter to a large extent, and gives the printed matter new functions. An important means of value-added printing and promotion. Therefore, indentation technology has received more and more attention from the industry, and the scope of its use has become wider and wider. However, in the die-cutting and creasing process, a series of problems often occur, which affect the smooth progress of production. For this reason, this article takes the common problems in the production of die-cutting and creasing with the horizontal flat die cutting machine as an example to analyze , I hope to help the actual production.
Common indentation problems:
Fully automatic horizontal die-cutting machine, the principle of paper feeding and delivery is similar to that of offset printing machine. The faults are not analyzed here. The following is only an analysis of common problems in the die-cutting part.
We know that indentation is a line mark caused by folding, squeezing or wrinkling. The entire process of indentation is: design-proofing-typesetting-plate installation-pad plate-boot-finishing-finished product. In the manufacturing process of folding carton, the line mark is a controlled deformation on the cardboard. The principle of indentation is that the cardboard is pressed between two fixed surfaces (concave mold and convex mold). The internal fiber structure of the paper is destroyed, causing partial layering of the paper, and concave and convex line marks are formed on the outside. When the indented cardboard is folded at ninety degrees or one hundred and eighty degrees, the fiber bonding (cohesion) inside the paper is completely separated.
In the process of indentation, the pressure is uneven, there are generally two situations: one is slight unevenness. If the pressure is slightly uneven, it may be due to the uneven distribution of die-cutting knives and wires (steel knives, steel wires), causing the moving platform to be skewed during die-cutting. At this time, it should be installed on the die-cutting plate. Balance the knife line to make the platform evenly stressed. It may also be affected by the direction of paper fibers. When the paper is perpendicular to the cutting line, the indentation effect is ideal. The other is serious unevenness. If serious pressure unevenness occurs at the four corners of the front and rear of the platform, it is mainly caused by the inconsistent height of the four connecting rods supporting the movable platform. At this time, the protective cover of the die-cutting base should be opened to check whether the swing rod is worn or not. If the wear is serious, it needs to be replaced. Otherwise, the four pressure adjustment inclined irons need to be adjusted until the pressure is consistent.
Burst line (burst color)
When the indentation die (punch) steel wire 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 great, the outer monster will break when the cardboard tension is exceeded (the cigarette box bursts when it is packed). During the die-cutting process, the surface tension of the cardboard will increase with the increase of the number of impressions on the cardboard. 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.