Sample files for use with the examples are available from the Downloads page.
Expand the downloaded ZIP archive into a convenient directory from which to run Local Simulation inside the numbered directories.
Problem description
For this example, you will run commands inside directory 16.
A simulation of a laser powder bed fusion build of a generic geometry from Inconel 625 on a SAE 304 build plate is completed using generic processing conditions, then the heat treatment of the component is modeled using two different heat treatment cycles. The substrate or build plate is assumed to be 25 mm thick. The resulting mesh is illustrated in Figure 1.
Figure 1: Autogenerated mesh
A time incremental thermal analysis is performed first to compute the temperature history of the part. Layers are activated in groups, and additional time increments are used to model heat conduction into the part. The thermal analysis includes only the part and substrate. Heat loss into the powder is modeled as convection with a value of 25.d-6 W/((mm2)°C) using the *CONV option.
A time incremental mechanical analysis is performed after the thermal analysis is completed, using quantitative stress analysis settings. Similarly to the thermal analysis, layers are activated in groups using *PBPA, and the computed temperature distribution from the mechanical analysis is used to compute deformation due to the thermal expansion.
At the end of the build simulation heat treatment of the component and build plate is modeled using a sample heat treatment schedule to stress relieve the part. The build plate is heated to 899° C over half an hour, held at 899° C for 2.5 hours, and then cooled down to ambient temperature over 3 hours. The aim of the stress relieving temperature is to remove around 90% of the residual stresses of the as-built part. During this simulation, restart files are written using the *ORES control card.
A second heat treatment cycle is modeled using the exact same model and processing conditions. Using the *REST card, this can be achieved without having to rerun the process simulation. The heat treatment cycle begins at the end of the processing model, using the previous model results. The new heat treatment cycle heats the chamber to 700° C over the course of 2 hours, is held at a constant temperature for just under 4 hours, and cooled to room temperature in almost 6 hours.