The injection molding time mentioned here refers to the time required for the plastic melt to fill the mold cavity, excluding auxiliary time such as mold opening and closing. Although the injection molding time is very short and has little impact on the molding cycle, adjusting the injection molding time plays a significant role in controlling the pressure of the gate, runner, and cavity. Reasonable injection molding time helps to achieve ideal melt filling, and is of great significance for improving the surface quality of products and reducing dimensional tolerances.

The injection molding time is much lower than the cooling time, approximately 1/10-1/15 of the cooling time, which can be used as a basis for predicting the entire molding time of plastic parts. When conducting mold flow analysis, the injection time in the analysis results is equal to the injection time set in the process conditions only when the melt is completely driven by the rotation of the screw to fill the cavity. If the pressure maintaining switch of the screw occurs before the cavity is filled, the analysis result will be greater than the set process conditions.