Analysis of problems related to die-cutting of foam materials and the use of engraved cutting dies

In our daily die-cutting process, there common issues encountered during the die-cutting of foam materials and the advantages of using engraved cutting dies for foam material die-cutting. Today, let's analyze these issues related to foam materials together.

Foam Classification: Foam can be divided into sponge and foam.

In the die-cutting industry, whenever foam materials are involved, they share a common characteristic of being relatively soft compared to other materials. Therefore, during the die-cutting process, there will be varying degrees of deformation. Whether it's sponge or foam, they are rarely used alone; usually, a layer or multiple layers of adhesive are used together.

Foam properties include compression ratio, thickness, density, hardness, color, and other main characteristics. The compression ratio refers to the maximum extent to which the foam can be compressed. For example, if a compression ratio of 95% is required, it means that the foam will be cut only when it is compressed to 95% of its original thickness.

Commonly used foam materials for die-cutting include PORON, Saint-Gobain, EVA, EPDM, sound-absorbing foam, PU foam, and so on.

1. Issues encountered during foam die-cutting: Deformation is a common issue due to the softness of foam. When the die exerts pressure on the foam during cutting, it tends to flatten and then separate it. The die has both inner and outer parts, and when the internal pressure exceeds the external pressure during the die-cutting process, it can cause deformation in the cross-section. Sometimes, concave or tilted sections can appear. Ideally, a correctly die-cut foam will have a straight cross-section, while an improperly cut foam will have a curved cross-section.

2. To simultaneously cut and remove waste material, water jet cutting or the method of using two dies together can be used. However, some craftsmen may not achieve clean and precise cutting of the product while efficiently removing waste material. In reality, with the right choice of cutting dies and the skills of the craftsmen, this issue can be addressed effectively.

Issues with water jet cutting: Higher cost, approximately twice the cost of die-cutting; significantly lower production capacity, about one-tenth of die-cutting.

Issues with two-die cutting: The main problem is a high defect rate, as the two dies may not align perfectly. However, if the two dies align perfectly, the cross-section will be very smooth and beautiful. If concentric circles are not required, a single die can achieve the same result, producing visually appealing products. Two-die cutting can be done for foam materials with a thickness of 3mm or more. If the foam material is large, there won't be a significant difference in internal and external pressure, resulting in a clean and attractive die-cut product.

What to do if the cut surface is not perpendicular?

This issue mainly arises when using two dies for cutting, and if the edge being cut is relatively small, it can result in a non-perpendicular cut. However, if the craftsman properly adjusts the die before die-cutting, it's possible to reduce pressure during the cutting process, allowing the die to retract on its own and relieve the pressure. This, in turn, ensures higher precision in the die-cut products.