Among the die-cut parts we process, EVA foam die-cutting is often encountered. The normal thickness will be 1-2mm, and the final ones may reach 5mm. For the processing of this foam, in the consumer operation In the process, you will definitely encounter many problems of one kind or another. Then the problems we often encounter are mainly manifested in the following three points:

1. It is easy to present the beveled edge 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. Regarding some hole-shaped products, it is difficult to discharge waste (the pore size of the small hole is too small, the thickness of the foam is large, and it is difficult to complete the discharge);

This is a very common phenomenon that we encountered during the EVA foam operation. Below, Xiaobian will take the above three common problems and stop the analysis, and give the relevant treatment plan; we have the characteristics of EVA foam itself. Everyone makes a simple introduction: EVA foam has a high thickness, a certain elasticity, low elastic limit, and easy to dust. Due to the above characteristics of EVA foam, it will lead to the three fundamental problems we have mentioned before in the EVA foam die cutting process;

Bevel problem

First of all, regarding the beveled edge which is easy to be presented during the die-cutting and punching process, the reason for this problem is that the foam has a high thickness, is punched in the punching process, is pressed after the foam is pressed, and the foamed surface is pressed. Beveled, the main way to deal with such problems is to change the choice of tool.

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

At the same time, regarding the relatively simple construction of EVA foam die-cutting parts, we use the method of striping, dividing, and skipping to reduce the factor that affects the bevel edge, so as to reach the problem of avoiding the bevel. With regard to some products with slightly complicated construction, we can die cutting by means of stopping the knife line synthesis, without closing the knife line, multi-wire stacking method, reducing the crushing stress in the foam punching process, to reduce the foaming inclination. Side problem.

Debris dust

Secondly, regarding the problem of EVA foam crumb dust, the basic reason for the formation of such a problem lies in the characteristics of the foam itself. Because the foam has low toughness, the composition is foaming data, and everything is in the blanking process. Repeated action of the cutter, the crumb foam particles easily form dust and float in the air. There are a variety of ways to deal with such problems with die-cutting operations with clean requests. Commonly used are squirting and squeezing agents, and the usual method on the production line is to combine a layer of OPP maintenance film on the EVA foam surface. Handle this problem. Of course, this treatment may result in the cost of some accessories.

Difficulties

Thirdly, regarding the problem of the waste of waste in the form of holes, the most basic reason for the formation of such causes is that the foam is too thick, and at the same time, the small pore size causes the waste to be extracted and formed. The common practice is to make a set of thimble jigs outside the die-cutting machine mold base to stop the waste discharge, and to push out the hole-shaped waste through the thimble to stop the waste material from being discharged. However, this kind of waste disposal method is not good, and it is easy to scratch the foam and form a bad product. The commonly used method on the round knife is to stop the extraction of the waste operation. Today, with regard to the generation of such problems, Xiao Bian gives a better work plan, which is the asynchronous work plan.

Processing plan - asynchronous work

Fourth, the benefits of the asynchronous work plan; everyone knows that the asynchronous data is pulled asynchronously, and the underlying data is synchronously die-cut, and the purpose of the data is reached. Here, we have stopped the foaming and supporting the bottom film by the asynchronous method, which not only saves the foam data, but also removes the outer layer of the material while the upper layer is taken away. It is also taken away at the same time, and the oblique side is also greatly improved due to the effect of stress. Moreover, after this type of operation, the fundamental dust problem has also been effectively dealt with.

The above is the introduction and treatment of the three fundamental problems in the process of EVA foam punching. If you have different opinions or better working methods, please feel free to discuss and exchange.