Flat Press Die Cutting Technology and Analysis of Related Problems (3)

Die-cutting part-4. Problems in die-cutting process

(4) Die-cutting and dusting When die-cutting, the phenomenon that the die-cutting products are not smooth and fluffy often occurs, and in particular, some cut-edges closer to the indentation line are more serious. This is due to die cutting of the strips during die-cutting. The indentation steel wire has a pulling force on the paper, and the paper is pulled when the paper is not completely cut.

To solve this problem, we must first choose different types of die cutters according to the paper. Die cutting knives include straight knife and horizontal knife, the two lines of the blade have a high and low points. The lines and heights formed by the blade are directly related to the die cutting quality of different types of paper and the service life of the die cutter. In the avoidance of paper hair, the straight knife is better than the horizontal knife; in the service life, the low front knife is better than the high front knife. When die-cutting coated paper jams should be used straight ruled high front knife, and require the blade is grinded, it is best not to use a concave and convex molding process, or too much pressure will have a great impact on die-cutting. In the processing of ordinary cardboard should use a small front knife, and according to the quality of the paper fiber to determine the knife's grain. When the die-cutting fiber is poor or thicker, a straight knife is used, and when the fiber quality is better, a horizontal knife can be used to improve the service life of the knife.

It is also possible to affix a 60° arched strip to the die cutter near the indentation steel line, reducing the pulling force of the indentation steel wire near the die cutter to the paper when the die is cut and pressed. Such as die-cutting is 300g / m2 paper is usually selected 0.4mmxl. 3mm indentation line, 23.4mm high indentation steel wire, in case of failure can be changed to 0.4mmxl. 2mm indentation line, 23.3mm high point indentation steel wire. In this way, the pulling force on the paper when the die-cutting and pressing is reduced, and the problem of fluffing can basically be solved.

The use of sandwich steel stencils is the best way to solve paper-failure problems, but due to the high cost of such die-cuts, it cannot be widely accepted by packaging and printing plants.

(5) Die-cut "glue"

Die-cut "glue" refers to the paper sticking to the die plate. The reasons for this failure are: the density of the sponge strip glued around the die cutter is too small or the hardness is too low, and the resilience is insufficient; the cutting edge of the die cutter is not sharp and the paper is too thick, causing the knife to stick when cutting or cutting. According to the distribution of die cutters, sponges of different hardness can be reasonably selected or die cutters can be replaced.

(6) Die-cutting "random"

Die-cutting is mainly related to platemaking process and sponge tape.

If the shape of the work is complicated or there are many jobs, and the dots on the die plate are both small and small, it is easy to cause die-cutting. In this regard, we must appropriately increase the number of links. In addition, when making a die cut, try to keep the print length direction consistent with the feed direction.

The release paper strip glued on the die-cut plate has a low hardness and is too soft to smoothly remove the paper from the die cutter or the indentation steel wire. The solution is to replace it with a high-quality sponge with a good elasticity. (to be continued)