In the Build Settings step of our workflow, we have already accounted for convection between the part to the surrounding gas in the chamber in both the Build Step and the Cooldown Step. There is one other area of heat transfer to consider and that is associated with the base plate.
During the printing process, the plate is typically heated on the bottom to maintain a constant, slightly elevated temperature. You may insert a temperature constraint or convection surface to simulate this during the build step. If the plate is not heated, perhaps apply a room condition convection surface, or set the surface boundary condition to adiabatic.
After the print process is complete, the base plate heating is removed and the built part cools to room temperature. This is simulated by a room-temperature convection surface applied to the bottom of the base plate in the cooldown step.
The time duration of the cooldown step is estimated based on the average part temperature at the end of the build, its volume, and material properties. Using the convection values and room temperature, the Mechanical application solves the simple heat transfer equation to get an estimate of the cool down time. It is only an estimate so you can extend it if required or put in a preferred time in analysis settings. One final step is performed to force all the temperatures to room temperature for the subsequent distortion and stress calculation.
Procedural Steps
To apply a temperature to the bottom surface of the base plate for the build step:
Right-click the Transient Thermal object and then select Insert > Temperature.
Select the bottom surface of the base plate (geometry selection) and hit Apply in the Details view.
In Details view, under Definition, Temperature, enter a temperature value for Magnitude. (In our example we use 80°.)
To apply room-temperature convection to the bottom surface of the base plate for the cooldown step:
Right-click the Transient Thermal object and then select Insert > Convection.
Select the bottom surface of the base plate (geometry selection) and hit Apply in the Details view.
In Details view, under Definition, Film Coefficient, enter a value for the convection coefficient.
Under Ambient Temperature, enter a value of 22°. (This may be the default.)