Pressure Adjustment Techniques During Injection Molding

During the injection molding process, the size of the injection molding pressure affects the quality of the molded product. The pressure in the injection molding process includes two kinds of plasticizing pressure and injection pressure, which directly affect the plasticization of plastics and the quality of molded products. The importance of pressure regulation for injection molding is self-evident. So how should the pressure be adjusted during the injection molding process?

1. Plasticizing pressure: When using a screw injection machine, the pressure generated by the melt on the top of the screw when the screw rotates backward is the plasticizing pressure. The plasticizing pressure can be determined by adjusting the relief valve in the hydraulic system. In the injection, the size of the plasticizing pressure is different due to the requirements of the injection molding product and the type of plastic. If the rotation speed of the screw is unchanged, the shearing effect after the plasticizing pressure increases will be strengthened, and the melt temperature will increase. The weakening of the chemical intensity, the increase of the countercurrent and leakage, and the increase of the driving power. The plasticizing pressure affects the temperature uniformity of the melt, the uniformity of the colorant mixing, and the size of the gas exhausted from the melt. In general operation, the plasticizing pressure should be as low as possible under the premise of ensuring good product quality. The value varies with the type of plastic used.

2. Injection pressure: In the production process, the injection pressure of most injection molding machines is based on the pressure applied to the plastic by the top of the plunger or screw. The injection pressure can reduce the flow resistance of the plastic from the barrel to the cavity, promote the rate of melt filling, and the pressure of the melt increases. In order to ensure the quality of injection molded products, pay attention to the pressure control method in the injection molding process. According to the required quality of the product, choose the appropriate pressure control method and pressure.