In the foam die-cutting parts we process, EVA foam die-cutting is often encountered. Generally, the thickness will be 1-2mm, and the final one may reach 5mm. For the processing of this foam, During the production process, there will definitely be many problems of one kind or another. Then the problems we often encounter are mainly manifested in the following three points:

1. The beveled edge is easy to appear during the die-cutting process of the foam (the rounded edge of the circular die is larger);

2. These thick foams are prone to generate debris dust during the blanking process;

3. For some porous products, it is difficult to discharge waste (the pore diameter of the small pore is too small, the thickness of the foam is large, and it is difficult to realize waste discharge);

This is a very common phenomenon we encountered in the EVA foam die-cutting process. Below, Xiaobian analyzes the above three common problems and gives relevant solutions; we have the characteristics of EVA foam itself. To make a simple introduction for everyone: EVA foam has a high thickness, a certain elasticity, low elastic limit, and easy to dust. Due to the above characteristics of EVA foam, there are three basic problems that we have mentioned before in the die cutting process of EVA foam;

1 bevel problem

First of all, regarding the beveled edge which is easy to appear in the die-cutting and punching process, the cause of this problem is that the foam has a high thickness, which is formed during the punching process, after the foam is extruded, and the foamed surface is pressed. Beveled, the main method for solving such problems is to change the choice of the tool.

Usually, the die-cutting tool we use is a double bevel cutting tool for punching. Therefore, in order to ensure the effective reduction of the production of the bevel, we use a single front knife, the inner straight outer oblique to cut, can effectively reduce the occurrence of foam bevel.

At the same time, for EVA foam die-cutting parts with relatively simple structure, we use striping, edge-dividing and skip-cutting methods to reduce the factor that affects the bevel edge, so as to avoid the oblique side problem. For some products with a slightly complicated structure, we can use the method of cutting the line to cut, do not make the closed line, multi-wire overlap, reduce the crushing stress in the foam cutting process, to reduce the foaming slope. Side problem.

2 crumb dust

Secondly, regarding the problem of EVA foam crumb dust, the root cause of this problem is caused by the characteristics of the foam itself. Because the foam has low toughness, the composition is foamed, all in the blanking process, because The repeated action of the cutter, the crumb foam particles are easy to form dust and float in the air. For some die-cutting operations with clean requirements, there are many ways to solve such problems. Generally, there are spray release agents, and the method often used on the production line is to laminate a layer of OPP protective film on the EVA foam surface. Solve this problem. Of course, this solution may cause some waste of accessories.

3 rows of waste

Regarding the problem of wasteful waste in the form of holes, the most fundamental reason for such causes is that the foam is too thick, and at the same time, the small pore size causes the waste to be extracted, which is difficult to extract. In the conventional practice, a set of thimble jigs is arranged outside the die-cutting machine mold base for waste discharge, and the hole-shaped waste material is ejected through the thimble to discharge the waste material. However, this method of discharging waste is not good, and it is easy to scratch the foam, resulting in poor product. The commonly used method on the round knife is to extract the knife for extraction and waste disposal. Today, for the generation of such problems, Xiaobian gives a better working plan, which is the asynchronous working plan.

The benefits of the asynchronous operation scheme; everyone knows that the material can be saved by asynchronously pulling the upper material and synchronously cutting the lower material. Here, we use the asynchronous method to separate the foam and the bottom film, which not only saves the foam material, but also removes the foam material at the same time as the upper layer is taken away during the actual operation. It is also taken away at the same time, and the oblique side is also greatly improved due to the effect of stress. Moreover, through this type of operation, the basic dust problem has also been effectively solved.

The above are the three basic problems and solutions that are often encountered during the EVA foam die-cutting process. If you encounter different problems or better working methods when encountering these problems, please feel free to discuss the communication!