Expandable beads compression molding
DATE：2021/11/26 8:31:13 / READ： / SOURCE：This station
Expandable beads compression molding
1. Molding processThe compression molding process refers to the pre-expanded styrene particles filled in the mold cavity, which are heated to soften the particles and further swell the particles under the action of the heated foaming agent and the heating medium. Due to the limitation of the mold cavity, the granular structure swelled by heat will be cooled and shaped to obtain a molded foam product.
2. Foam molding machine
The foam molding machine consists of a frame, a hydraulic cylinder, a steam box heating and cooling system and other components. The steam box in Figure 48 is made of aluminum gold, the upper suit has gears, the machine mold is used first, and then the pre-foamed beads are added to Denet, and then the plate is made through heating and cooling processes, and then Open the mold and take it out. Compression molding is divided into differential steam heating perforated tube steam heating (also called probe steam heating), hot gas heating, and conduction heating high-frequency heating methods.
The main component of the foam molding machine is a press, and the molding die is fixed on the press to open and close. According to the molding process and operation mode, it is divided into ordinary foaming molding machine, automatic foaming molding machine, vacuum foaming molding machine, etc. Ordinary foam molding machines are divided into vertical and horizontal hydraulic presses. The upper and lower molds on the forming mold are respectively fixed on the moving plate and fixed plate of the press, and the moving plate is driven by the press cylinder to open and close the mold. The automatic foam molding machine has feeding devices such as hoppers, automatic feeding guns, and is equipped with heating steam, driving compressed air, mold cooling water pipeline system, electrical control system, opening and closing mechanism, automatic ejection and ejection device, etc., forming The process is done automatically. The automatic foaming molding machine has high production efficiency and good product quality. The main compression molding process of part of the automatic foam molding machine is to fill the mold with the matured pre-expanded particles with a feeding gun, press the tool, and pass in the plain steam to heat the lower mold plate and make the steam pass through the small holes or the inner wall of the mold. The slot enters the mold cavity. Under the condition of steam heating, the pre-expanded particles are softened, expanded, and fused into a whole, cooled and demolded through water, and then dried in an oven at 50-60°C to remove surface gas on the product.
The density of the foamed product is directly related to the density of the pre-expanded particles and the molding pressure (steam pressure). The compression molding pressure should be selected according to the density of the pre-expanded particles. When the molding pressure is controlled at 0.06～0.25MPa, the density of the foamed product is 20300kg/m3, and the molded foamed product generally adopts a slower cooling method to make the surface of the product thicker, smoother and smoother. The cooling time can be selected according to the density and wall thickness of the foamed product during the curing time of the pre-expanded particles.
Author：admin