1, the temperature of the barrel. 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, it is not good to plasticize plastic parts, dents, and lack of material defects; on the contrary, if the temperature is too high, it will cause splashing, the nozzles will flow, the color will become darker, the mechanical strength will decrease, and even degradation will occur. Generally, the barrel temperature is controlled at 240 to 280 °C, and the glass fiber reinforced PET barrel temperature is 250 to 290 ° C. The temperature of the nozzle should not exceed 300 °C, and the temperature of the nozzle is usually lower than the barrel temperature.

2, mold temperature. The mold temperature directly affects the cooling rate and crystallinity of the melt, the crystallinity is different, and the properties of the plastic parts are also different. Usually, the mold temperature is controlled at 100 to 140 °C. Smaller values ​​are recommended when forming thin-walled plastic parts. When forming thick-walled plastic parts, it is recommended to have greater value.

3. Injection pressure. The PET melt is fluid and easy to form. Usually, medium pressure is used, the pressure is 80 to 140 MPa, and the glass fiber-reinforced PET has an injection pressure of 90 to 150 MPa. The injection pressure should be determined by considering the viscosity of the PET, the type and amount of the filler, the location and size of the gate, the shape and size of the plastic part, the mold temperature, and the type of injection molding machine.