The problem
Feeding decisions depend on where and when the metal freezes last: where risers go, where a chill helps, whether a sleeve is needed. A full process simulation answers that, but it takes setup time and licences, so early in design many of these decisions are still made by rule of thumb.
What I built
FoundryFlash takes a STEP model to a solidification answer in the browser. It has two engines. The GNN surrogate screens a design in seconds; that is the version described in the trade articles below. The full solver described here is for the final check.
Solidification time on a flanged casting in the FoundryFlash viewer.
The solver is written in Julia. It uses control-volume finite elements on linear tetrahedra and an enthalpy formulation, so the latent heat released during freezing needs no special handling. Time stepping is implicit, solved with a preconditioned conjugate-gradient method, and the mould is a region of its own with a heat-transfer coefficient at the interface. The same code runs on CPUs and on NVIDIA GPUs through CUDA.jl, and the two give results identical to round-off (10⁻¹⁵). Gmsh meshes the casting and the sand mould with its parallel HXT mesher.
On the web side, a FastAPI backend keeps a solver process warm, and a React and three.js viewer shows solidification time, fraction liquid, temperature and thermal modulus. The viewer masks hot spots, helps size feeders and writes a PDF report.
Results
| What | Measured |
|---|---|
| Full solve, 1.6M elements | 9.9 s on an RTX 3060, 44.9 s on 8 CPU threads |
| 3D meshing, 1.6M-element test body | 57 s before, 4 s after (14× faster) |
| Job start-up | about 27 s before, under 0.1 s after |
| Verification against an independent FEniCSx reference | solid-fraction MAE 0.0086 |
| Comparison with a commercial simulation of a production casting | +51% at first, 3.7% after a sensitivity study traced the gap to the mould's thermal properties |
| Automated tests | about 7,500 in Julia, Python and TypeScript |
Status
FoundryFlash is my own product and is still in development. The source code is private; I can share technical details on request.