What is the impact of different types of label material surface materials on die-cutting? In general, the factors that affect the quality of surface material die-cutting include the type of surface material, the strength of the surface material and the thickness of the surface material
① Type of surface material.
Surface materials are basically divided into two types: paper and film. The cutting principle of paper is slightly different from that of film materials. Although in theory, the surface material and adhesive must be cut through together during die-cutting, in fact, die-cutting paper materials is a combination of the cutting of the tool and the self-fracture of the paper after being stressed, that is, the blade cuts downward while squeezing on both sides of the paper, and the paper breaks after being stressed.
Therefore, the die-cutting accuracy of paper materials is relatively not very high. When analyzing samples, we often see that some labels have burrs. This is due to the coarse fibers of the material itself and the phenomenon of natural fracture.
Based on the die-cutting principle of paper materials and considering the wear of the blade, the angle of the flattening blade of paper is usually 52°. Because the angle is large, the extrusion deformation of the material during die-cutting is large, and the horizontal separation force facilitates the separation of the material. But don't misunderstand that it is OK to die-cut paper materials to two-thirds of the thickness. If this happens, it will bring other problems such as difficulty in waste discharge and glue seepage. Therefore, we firmly advocate 100% cutting of surface materials and adhesives.
The die-cutting principle of film materials is simply the principle of complete cutting. Because most film materials are tough and will not break naturally, the theory of cutting through two-thirds is not suitable. The entire thickness must be completely cut through or at least four-fifths of the thickness must be cut through, otherwise the waste edge of the waste discharge will be peeled off together with the label.
For this reason, the blade for die-cutting film materials should have a sharp blade, high hardness, and a small blade angle, usually 42 degrees. If a large-angle die-cutting knife is used, not only will die-cutting be difficult, but if the blade is not sharp, the surface material will not be cut through and the base paper will break first, and the edge of the finished label will be flanging, causing glue seepage.
In short, the precision of die-cutting film is greater than that of paper materials, so die-cutting film materials has certain requirements for equipment precision, die-cutting plate precision and base paper.
② Strength of surface material.
The strength of the surface material is related to its thickness, fiber (resin) structure and its own water content. In the die-cutting process of self-adhesive materials, the biggest influence on the strength of the surface material is the waste discharge situation, or the waste discharge speed. The waste discharge speed is related to productivity, and we hope to have a high waste discharge speed. The humidity of the village material directly affects its own strength. The humidity is related to the environment. When the environmental humidity is high and the material is damp, its own strength will weaken, it is easy to break, and even cannot be discharged. Therefore, it is necessary to control the temperature and humidity in the production environment and storage environment to prevent the material from getting damp. When designing the layout, according to the strength of the material, the waste discharge size and waste discharge speed of the label should be reasonably arranged through experiments, which can improve productivity and reduce material waste.
③ The thickness of the surface material.
The thickness of the material directly affects the depth of die-cutting. The thicker the material, the easier it is to die-cut, and vice versa, the thinner the material, the more difficult it is to die-cut. Because the tolerance of die-cutting can be larger for thicker materials, and the tolerance of thinner materials is smaller, the probability of cutting through the base paper is greater. We have done an experiment, die-cutting two materials of 80g and 60g surface materials on the same flat-press label machine, and their base paper is the same. The experimental process found that the 80g material die-cutting waste discharge is normal, but when the 60g material is changed to die-cutting, waste discharge breaks, base paper cutting and label falling off often occur. Frequent shutdowns and repeated padding waste are very wasteful, and some customers complain that there is a problem with the material. There are many reasons for this kind of situation. If the round-to-round die-cutting method is used or the die-cutting area is reduced and high-precision equipment is used, this phenomenon can be avoided or reduced.
Therefore, when die-cutting thin surface materials, it must be done on high-precision equipment, and the die-cutting area (especially small labels) must be minimized. Die-cutting plates made by professional die-cutting plate manufacturers should be used. In addition, attention should be paid to the padding accuracy. The thickness of the surface material is proportional to the strength, which directly affects the waste discharge speed. We used 80g and 60g materials for waste discharge comparison tests respectively; the results showed that the former had a 20% to 30% higher production efficiency than the latter, and the product quality was also good.
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