Forming process of epp core foam material

Forming process of epp core foam material

Summary:1.Clamp the mold and preheat the mold to make the surface te...
1.Clamp the mold and preheat the mold to make the surface temperature of the mold reach the melting point. Feed, so that the raw material enters the mold through the feed gun. Steam is passed into the mold, and the steam is flushed from top to bottom to push the air out of the steam chamber and the condensed water to flow out. During this process, open the steam inlet valve above and the condensate drain valve below. Lateral steam sweeps the steam from one side of the steam chamber to the feed, penetrating the feed and reaching the other side. At this time, close the condensate valve on one side and open the steam inlet valve.

2. At the same time, close the steam inlet valve on the opposite side and open the condensate valve, so that the steam is ejected from the opposite direction. If there are thin flanges in the mold, steam should pass around the flanges so that the material trapped in the flanges can also be melted. After the steam is passed laterally, it needs to go through the process of pressure maintenance or double-sided steaming. During this process, open the steam inlet valve and close the condensate drain valve, so that the pressure gradually peaks.

3. After the steam is introduced, the temperature inside the mold will generally reach 140 ℃. In order to ensure the smooth release of the product, the mold temperature must be lowered to 70°C. Once the internal pressure is released and the temperature is lowered to the allowable demolding temperature, the demolding operation can be carried out. Dry to shape. Generally, the drying temperature is set to 60 ℃ ~ 80 ℃, and the drying room should be kept dry and well ventilated.

4. There are two types of core foam: hard and soft. Rigid foam is at room temperature, and the polymers that make up the foam are in a crystalline or amorphous state, and their glass transition temperature is higher than normal temperature, so the texture of foam is harder at normal temperature. Flexible foam, that is, the melting point of the polymer constituting the foam is lower than normal temperature, or the glass transition temperature of amorphous polymer is lower than normal temperature, and the material is soft at normal temperature.

5. Semi-rigid or semi-flexible foam, which is a foam between the above two categories. Foams can also be divided into two categories: low-foaming and high-foaming. Usually, the foaming ratio (the multiple of the volume increase after foaming compared with that before foaming) is called low foaming, and the foaming ratio greater than 5 is called high foaming.