What are the injection molding conditions for PET?

What are the injection molding conditions for PET?

1. The temperature of the bucket. The molding temperature range of PET is very narrow, and the temperature directly affects the performance of the product. If the temperature is too low, it is not conducive to the manufacturing of plastic products, increasing the possibility of defects in injection molded parts; On the contrary, if the temperature is too high, it will cause the material at the nozzle to overflow, discolor, reduce mechanical strength, and even cause degradation. Usually, the temperature of the material barrel is controlled at 240~280 ℃, and the temperature of the material barrel for glass fiber reinforced PET is 250~290 ℃. The temperature of the nozzle should not exceed 300 ℃, and the temperature of the nozzle is generally lower than the temperature of the material barrel.

Injection mold temperature. The temperature of injection molds has a direct impact on the cooling rate and crystallinity of the melt. Different crystallinity results in different properties of plastic products. The temperature of injection molds is usually controlled between 100~140 ℃. When forming thin-walled plastic parts, the temperature of the injection mold should be controlled within a small range; When forming thick walled plastic parts, the mold temperature should be relatively high.

Injection pressure. PET melt has good flowability and is easy to form. Generally, medium pressure is used, with a pressure of 80-140MPa, and the injection pressure of glass fiber reinforced PET is 90-150MPa. The determination of injection pressure should consider the viscosity of PET, the type and quantity of fillers, the position and size of the gate, the shape and size of plastic parts, mold temperature, and the type of injection molding machine.