The injection location temperature moves toward the mold temperature during the packing and cooling phases because there is negligible flow from the barrel during these phases.
The injection location temperature affects the flow of the melt into the part during packing, usually by decreasing the flow. To achieve realistic warpage values, it is important to take the injection location temperature into account during the packing and cooling phases.
The cooling calculation at an injection location starts when the flow rate there drops below a small injection cooling criterion. The criterion is a very low flow rate value, sufficiently small that the subsequent influence of barrel temperature on the injection temperature is negligible. Once a location has started cooling, it will continue cooling regardless of the flow rate. Different cooling calculation methods are used depending on the type of model that you are analyzing. In all cases, the appropriate local mold temperature values, HTC values and temperature-dependent material properties are employed