Adhesive materials breaking or failing during waste discharge? These reasons should not be ignored!

It is a common phenomenon for adhesive label materials to experience edge tearing during die-cutting. Once tearing occurs, operators have to stop the machine to reorganize the waste edges, which results in reduced production efficiency and increased raw material wastage. So, what are the causes of edge tearing during die-cutting of adhesive label materials, and how can they be addressed?01 Low tensile strength of the material itself leading to edge tearingSome materials, such as coated paper (also known as mirror art paper), have short fibers and are relatively brittle. During the die-cutting and disposal process, the tensile strength of the waste edge is lower than the waste pulling force of the equipment, making it prone to tearing.In such cases, it is necessary to minimize the waste pulling force of the equipment as much as possible. If adjusting the pulling force to the lowest level still does not solve the problem, the waste edge should be designed wider during the early stage of process design to ensure that edge tearing does not occur frequently during die-cutting.02 Unreasonable process design / Too narrow waste edges leading to tearingMany labels for variable data printing on the market have easy-tear dotted lines. Some adhesive label processing companies, due to equipment limitations, have to place the dotted line and the border die on the same die-cutting station. Additionally, influenced by cost and price factors, the waste edge is often designed to be very narrow, usually only 1mm wide. This die-cutting process places very high demands on label materials, and any carelessness can cause edge tearing, thus affecting production efficiency.It is recommended that adhesive label processing companies, whenever possible, separate the easy-tear dotted lines from the label borders during die-cutting. This not only reduces the frequency of edge tearing but also greatly increases die-cutting speed. For companies without such conditions, adjustments can be made by modifying the dotted line proportion or removing parts of the dotted line that extend beyond the label border.03 Raw material defects leading to edge tearingDefective spots in adhesive label materials can also cause edge tearing. This problem is relatively easy to detect and will not be discussed in detail here. It should be noted that some defective edges in adhesive materials are small and not easy to notice; careful inspection is required. When such issues occur, remove the defective materials before die-cutting.04 Excessive adhesive flow or too much adhesive coating leading to edge tearingThe amount of adhesive applied to adhesive label materials significantly affects their die-cutting performance. Generally, after die-cutting on the equipment, the adhesive material is not immediately moved to waste removal but is transported a certain distance before reaching the waste station. If the adhesive is coated too thickly, it may flow back during transportation from the die-cutting station to the waste station, causing already cut label surfaces to stick together, which results in tearing when pulling the waste edges.Generally, the coating amount for water-based acrylic adhesives should be between 18–22 grams per square meter, while hot-melt adhesives should be between 15–18 grams per square meter. Exceeding these ranges significantly increases the likelihood of waste edge tearing. Some adhesives, even in small amounts, can cause waste sticking due to high fluidity.

When encountering this type of problem, you can first observe whether there is a severe stringing phenomenon between the waste edge and the label. If the stringing is serious, it indicates that the adhesive coating is too thick or has high fluidity. This issue can be resolved by applying some silicone oil additive to the die cutter or by heating it with an electric heating rod. The silicone oil additive can effectively slow down the adhesive backflow, while heating the pressure-sensitive adhesive material can quickly soften the adhesive, thereby reducing the degree of stringing.

05 Die Cutter Defects Leading to Waste Edge Breakage

Defective die cutters can also easily cause the waste edge to break. For example, a small notch at the edge of the blade can prevent the adhesive face material from being completely cut. The uncut parts bear more stress compared to other areas, making them prone to breakage. This phenomenon is relatively easy to identify, as the break occurs at a fixed location. In such cases, the damaged die should be repaired before it is used for die cutting.