Analysis of the Problems of Foam Accessories in Die Cutting Processing and Knife Die Punching

Classification of foam: Foam can be divided into two types: sponge and foam.

In the die-cutting industry, as long as the products are foam, these materials have a common characteristic. Compared to other materials, the material is relatively soft, so there will be varying degrees of deformation during the die-cutting process. Whether it is sponge or foam, they are rarely used separately and are usually prepared with one or more layers of adhesive for use.

The properties of foam include compression ratio, thickness, density, hardness, color, and other key characteristics. Compression ratio refers to the maximum amount of compression that can be achieved. For example, if a ratio of 95% is required, it can be understood that during the die-cutting process, it will only be cut after being compressed to 95% of the overall thickness.

The commonly used foam materials for die-cutting are: PORON、 Saint Gobain EVA、EPDM、 Acoustic foamPU foamWait.

The situation encountered when cutting foam: deformation, because the foam is very soft. When the knife is used to punch, it squeezes the foam flat and then cuts it, because the knife mold has an inner and outer division. When the internal pressure is greater than the external pressure during punching, it will cause the cross-section to deform, sometimes resulting in concave or tilted situations. The correct foam has a straight cross-section after punching and cutting. If the cross-section is not well punched, it will be bent.

To flush out foam and discharge waste at the same time, use water cutting method or two knife cutting method. However, some masters may not be able to cut the product straight and dispose of waste, but this situation can be achieved with the selection of the cutting die and the skill of the master.

The problems with water cutting include high cost, which is twice the cost of die-cutting; The production capacity is very low, and it is only one tenth of that of die-cutting.

There are problems with two blade cutting: the biggest problem is the high defect rate, which means that the two blades may not be aligned. But if the two knives are aligned, the cross-section is very beautiful, but if they are not aligned properly, it can be achieved with one knife without concentric circles, and the cut product is very beautiful. The dual blade position of the product can be cut at 3mm or more. Both are foam, if it is very large, there will not be a significant difference in internal and external pressure. The products cut by punching are also very beautiful.

What if the cutting surface is not perpendicular?

When cutting with dual blade positions, if the edge is relatively small, it may not be perpendicular. However, if the master adjusts the mold properly, there can be no pressure during punching, and the blade can be retracted by itself to relieve the pressure. Thus, the precision of the products produced by punching is higher.