Problems encountered in EVA foam products processing

Among the die-cut parts we know, EVA foam product processing is often encountered. Generally, the thickness is 1-2mm, and the thickest may reach 5mm. For the processing of this eva foam, it will definitely be encountered during the production process. There are many problems, and the problems that are often encountered are mainly manifested in the following points.

1. Beveled edges are easy to appear in the process of eva foam punching, and the beveled edges of round knife die-cutting are larger.

2. The eva foam of these thicknesses is easy to produce debris and dust during the punching process.

3. For some porous products, it is difficult to remove waste, the pores of the small holes are relatively small, the thickness of the foam is large, and the waste removal is not easy to achieve.

This is some common phenomenon we encountered in the process of EVA foam operation. I will give you a simple analysis on the characteristics of EVA foam itself. EVA foam has a high thickness, has a certain degree of elasticity, and has a low elastic limit, which is easy to generate dust. The eva foam has the above characteristics, which leads to the first three problems in the eva foam die-cutting process.

Hypotenuse problem

First of all, beveled edges are prone to appear in the process of die-cutting and stamping. The reason for this problem is that the thickness of the foam is high. The main way to solve such problems is to change the choice of tools.

The commonly used die-cutting tool is a double-beveled cutting tool for punching. Once again, in order to effectively reduce the impact of the generation of beveled edges, a single-edged knife is used for punching with an inner straight and an outer bevel, which can effectively reduce foam. The generation of hypotenuse.

At the same time, for the simple structure of eva foam die-cutting parts, we adopt the method of slitting, splitting, and skipping to reduce the factors that affect the beveling, so as to avoid the problem of beveling. For some products with a slightly complex structure, we can The cutting method is used to decompose the cutting line, instead of closing the cutting line, and the way of overlapping multiple cutting lines, to reduce the extrusion stress during the foam punching process, so as to reduce the generation of beveled edges.

Debris dust

Regarding the problem of EVA foam debris and dust, the root cause of this problem lies in the characteristics of the foam itself. Due to the low foam toughness and the composition structure of the foam material, during the stamping process, due to the repeated action of the tool, Debris foam particles easily form dust and float in the air.

For some die-cutting operations that require cleaning, there are many ways to solve such problems. Generally, release agent can be sprayed. The method often used in production lines is to compound an OPP protective film on the surface of the EVA foam to solve this problem. . Of course, this solution may cause some waste of auxiliary materials.

Difficult to eliminate waste

Regarding the difficulty of discharging waste, in fact, the root cause of this kind of reason is that the foam is too thick, and at the same time, the small hole diameter causes the waste to be difficult to extract during the waste discharge process. The general traditional method is to make a set of thimble fixtures outside the die base of the die-cutting machine to discharge waste. The hole-shaped waste is ejected through the thimble, and the falling material is discharged.

However, this kind of waste discharge method is not easy to operate, and it is easy to scratch the foam and cause product failure. The commonly used method on the round knife is the extraction knife for extraction and waste disposal. Today, for the occurrence of such problems, the editor gives a better job plan, which is an asynchronous job plan.

Solution-on asynchronous job

Everyone knows that the upper material is pulled asynchronously, and the lower material is synchronously die-cut to achieve the purpose of saving materials.

Here, we use the asynchronous method to separate the foam and the backing film to pull the material, which not only saves the foam material, but in the actual operation process, the upper layer of material is taken away at the same time, the foam outer frame waste It is also taken away at the same time, and due to the effect of stress, the hypotenuse will be greatly improved. Moreover, through this operation method, the basic dust problem can also be effectively solved.