Injection molding conditions of PET cosmetic cream jars

1. Barrel temperature. The molding temperature range of PET is narrow, and the temperature will directly affect the performance of the product. If the temperature is too low, the plasticization is not good, causing defects such as depression and lack of materials; on the contrary, if the temperature is too high, it will cause edge overflow, drooling of the nozzle, darkening of the color, reduction of mechanical strength, and even degradation. Generally, the barrel temperature is controlled at 240~280℃, and the barrel temperature of glass fiber reinforced PET is 250~290℃, not exceeding 300℃. The nozzle temperature is generally 10~20℃ lower than the barrel temperature.

2. Mold temperature. The mold temperature directly affects the cooling rate and crystallinity of the melt. Different crystallinity means different plastic part properties. Generally, the mold temperature is controlled at 100~140℃. When molding thin-walled plastic parts, it can take a small value; when molding thick-walled plastic parts, it can be a large value.

3. Injection pressure. PET melt has good fluidity and is easy to form. Generally, medium pressure is used, and the pressure is 80~140MPa. The injection pressure of glass fiber reinforced PET is 90~150MPa. The determination of injection pressure should take into account the viscosity, type and quantity of PET.