Why Self-adhesive Label Die-cutting Quality Problems Continue?

In the self-adhesive label production process, the quality of die-cutting will directly affect the label's post-processing process, and may even lead to poor products and increased scrap rate. Therefore, die-cutting link can not be ignored. This article introduces the quality requirements of die-cutting, die-cutting methods and some common factors that affect the quality of die-cutting.

Die-cutting Quality Requirements and Methods

Generally speaking, the die-cutting quality requirements for self-adhesive labels can be summarized as follows: the die-cutting knife does not damage the silicone oil layer while cutting through the adhesive layer, also known as "precise die-cutting", as shown in the figure. However, in the actual die-cutting production, die-cutting quality is often affected by the die-cutting method, equipment precision, die-cutting tool and self-adhesive material, and other factors, it is difficult to achieve this ideal situation.

At present, the label printing industry mainly uses flat die-cutting and round die-cutting two ways. From the perspective of die-cutting quality, round die-cutting has obvious advantages: high die-cutting accuracy and high processing efficiency.

The Main Factors Affecting the Quality of Die-cutting

1.The impact of label face material on die-cutting quality

At present, the commonly used self-adhesive surface materials are mainly paper and film two categories. Common paper materials are mainly composed of plant fibers and fillers, relatively easy to die-cut, generally rarely cause die-cutting quality problems, while film materials due to the strong toughness, especially PET materials, in the die-cutting is easy to cut through and other problems.

Therefore, in the choice of die-cutting knife, must choose the hardness treatment of the blade, the best can reach 58 Rockwell hardness or more, and the blade angle is best between 32 ° ~ 75 °, the smaller the angle the sharper the blade, it is also easier to cut through the film.

2.The impact of adhesives on die-cutting quality

Adhesives used in self-adhesive label materials can be divided into two categories: acrylic water-based emulsions and rubber-based hot-melt adhesives. Among them, acrylic water-based latex cohesion is small, easy die-cutting, die-cutting tools, die-cutting environment are no special requirements, can ensure a better die-cutting quality; hot melt adhesive intermolecular cohesion is larger, the requirements of the die-cutting process is more demanding, therefore, must be completely cut off the adhesive layer to ensure the normal discharge, otherwise the label will be taken away from the backing paper.

3.The impact of backing paper on die-cutting quality

Ensure the flatness of the backing paper is a very important factor in ensuring the quality of die-cutting, especially in the use of circular die-cutting process is particularly important. Because the height of the die-cutting knife above the base of the die-cutting plate is determined by the thickness of the backing paper, if the backing paper is not flat, the thickness is not uniform, part of the area will appear knife edge cut through the backing paper, cut through the surface material phenomenon, to the waste removal process brings trouble.

4.The impact of die-cutting tools on die-cutting quality

For round die-cutting, die-cutting knife and bottom rollers belong to the line contact, as long as the control of the pressure of the two points on the contact line, you can maintain the consistency of the die-cutting pressure, so the die-cutting accuracy is much higher than the flat die-cutting.

In addition to the above factors, the quality of die-cutting is also related to the technical level of the operator, workshop environment, static electricity, the precision of the die-cutting machine.