Casting

Casting simulations are performed using transient multiphase simulations using the VOF model with solidification. Conjugate heat transfer is applied between the solidifying melt and the solid mold.

Casting simulations allow you to assess the filling, solidification, and cool-down processes. They allows for defect prediction such as topological macro porosity prediction, micro porosity prediction, shrinkage due to phase change, trapped gas during filling, as well as cold shots or misruns. Casting simulation facilitates the design of gating and runner systems before start of production.

You require a separate license for accessing the casting metal database. This license is known as the Simcenter STAR-CCM+ Metal Processing Db add-on license.

The process for setting up a casting simulation in the Simcenter STAR-CCM+ simulation tree is outlined as follows:

1. Create a multi-region volume mesh with one region for the melt and one region for the mold.
   • If you set up an investment casting simulation, use the Offset Mesher to create shell molds.
2. Select the physics models for the melt .
   • If you run a pure thermal simulation, select the pure thermal model.
3. Select the physics models for the mold.
   • If you run a pure thermal simulation, select the variable density compensation model.
4. Use the Casting Material Database Editor to select the casting materials that you want to use in your simulation, and export the selected collection of materials to Simcenter STAR-CCM+.

   See Working With the Casting Material Database.

5. Use the imported casting materials in physics continua and assign the appropriate material properties as boundary values.

   See Using Imported Casting Materials and Properties in STAR-CCM+.

6. For the physics continuum of the melt, define the Eulerian phases for the liquid melt and gas.

   The liquid phase must be a single-component liquid and have a temperature-dependent density, such as User Defined EOS or Polynomial Density.

   See Defining Eulerian Phases.

7. For the Eulerian melt phase, select appropriate melting and solidification models. For pure thermal simulations, do not select the mushy zone or the slurry viscosity models.

   See Modeling Melting and Solidification

8. If you perform a sand casting simulation, select the wall porosity model for the gas phase. Wall porosity accounts for degassing that occurs when melt enters the mold and air is pushed into the sand mold.

   See Working with Wall Porosity.

9. Use the macro porosity model to detect shrinkage-related defects in a cast part.
   See Using the Macro Porosity Model to Detect Shrinkage-Related Defects.

   • If you run a pure thermal simulation, select the Macro Porosity (pure thermal) model.
10. If necessary, use the available criteria functions to post-process the simulation results.

    See Defect Prediction Using Criteria Functions.

11. To apply automated time-step control, select the Adaptive Time-Step model.

    See Setting Up Adaptive Time-Stepping.