Meaning
Simulation parameter in specialized injection molding software that defines the rate of heat transfer between the polymer melt and the mold steel. The moldex3d gap conductance value accounts for both the physical contact and the insulating effect of any air gaps that form during cooling. Accurate input of this value is required for the software to predict cycle times and warpage correctly.
Heat Flow
Conductance values change throughout the injection cycle. Initially, high pressure ensures a high moldex3d gap conductance because the melt is pressed firmly against the steel. As the part solidifies and shrinks, the value drops significantly.
This transition is modeled as a function of the local pressure and the temperature of the polymer.
Calibration Method
Small changes in the assigned conductance lead to large differences in the predicted part temperature at ejection. Users often calibrate the moldex3d gap conductance by comparing simulation results with experimental thermocouple data from a physical mold. Incorrect settings can lead to an underestimation of the cooling time needed.
This error results in parts that warp after they are removed from the tool. The sensitivity of the model to this parameter makes it a primary focus during the validation phase of a new project. Verification against real-world production data ensures that the simulation remains a reliable tool for future design iterations.
Cooling Optimization
Flow marks and silver streaks are often linked to the thermal history of the melt front. By using a realistic moldex3d gap conductance, the software can identify regions where the melt will freeze prematurely. This allows designers to move cooling channels or adjust wall thicknesses before the tool is cut.
Efficient heat removal is the primary goal of optimizing this parameter.
