Direct Energy Deposition Additive Manufacturing Workflow

Additive Manufacturing Scenario Creation guides you through the workflow for a sequentially coupled thermal-structural analysis using the direct energy deposition method to simulate the distortions and residual stresses that might occur during the 3D printing process.

A sequentially coupled thermal-structural analysis generally provides a more accurate simulation than an eigenstrain analysis. However, it also is more complex to set up and often takes longer to run than an eigenstrain analysis.

See Also
About Additive Manufacturing
Eigenstrain Additive Manufacturing Workflow
Thermal-Structural Additive Manufacturing Workflow

A typical workflow for a direct energy deposition additive manufacturing analysis is outlined below. Each step corresponds to the sections displayed in the Assistant.

Tip: Use the standard area of the action bar to activate the Assistant if it has been closed.
  1. Setup the model.
    • Create or select a finite element model.

      For existing finite element models, you must make selections for the thermal analysis and the structural analysis separately. When creating a finite element model, you can assign separate mesh sizes for the build geometry, the build tray, and the supports.

    • Define the shell thickness for the supports.
  2. Create the Meshes.
    • Create meshes for the printed parts, supports, and the build plate.

      The app automatically generates meshes for parts and supports that have associated slicing and scanning information and for the build plate.

    • Select additional meshing algorithms, if required.
  3. Define the Part & Support Properties.
    • Assign section properties to the model.

      The app creates section properties automatically if there is existing slicing data.

    • Connect the different parts together. Create tie connections between the part, supports, and the build tray.
  4. Define Starting Temperatures.
    • Define the chamber temperature for the thermal analysis case.

      In the thermal analysis case, the chamber temperature is the initial temperature of the printed part. It is assumed that the temperature of the incoming material is same as the chamber temperature.

      For example, in an FDM process, the initial temperature is the melting temperature of the material being deposited. No external heat source is modeled. In a laser direct energy deposition (LDED) process, the initial temperature of the powder material as it is being spread from the nozzle is the room termperature. The heat source (for example, the laser) is modeled independently as a moving heat flux.

    • (optional) Define an initial temperature for the build tray for both the thermal analysis and the structural analysis.
    • Define a melting temperature for the structural analysis case.

      In the structural analysis case, the melting temperature is the initial temperature of the printed part. For a part-level simulation, at material activation the initial temperature is the temperature from which the initial thermal contraction occurs. The melting temperature represents a relaxation temperature, above which thermal straining induces negligible thermal stresses. The melting temperature is used as the initial temperature for the material being deposited. For a detailed process-level simulation, the melting temperature should be set to the chamber temperature.

  5. Define the Material Deposition.
    • Select a support for material deposition.

      When used with existing manufacturing cell, printed parts are automatically selected.

    • Select a source type.

      Use the built-in source type if material deposition process can be approximated by a bead deposition with a rectangular cross-section. You can define the height, the width, and the orientation of the bead. Element activation sequence and the height and width of the bead are based on the toolpath data defined in an event series.

      If required, define your own (user-defined) source type and configure the interface to match custom user subroutine data that aligns with your additive manufacturing process.

  6. Define the Cooling to be applied to parts that have existing slicing data.
    • Define the convective and radiative cooling of the free surface as it evolves over the course of the print process.
    • Specify either convection or radiation or both.
  7. Define the Prescribed Temperatures.
    • If required, define any temperature boundary conditions for the thermal analysis.
  8. Create Structural Restraints & Loads.
    • Apply restraints to prevent rigid body motion of the part in the structural analysis.

      A clamp restraint is sufficient since there are no in-service loads being applied during the manufacturing simulation.

  9. Simulate.
    • If required, perform checks before solving the simulation.
    • If required, configure the simulation options, including selecting local or remote execution.
    • Start the solve.

      You can check or run only the thermal simulation or both the thermal and structural simulations.

  10. Postprocess the Results.
    • Create plots, and visualize the results.

      For example, you can create contour plots that display results using a spectrum of colors with corresponding values.

    • If required, create sensors that you can use in external simulations.