What Casting Process Simulation Changes Before The Mould Is Made

Where Defects Come From

A wear casting fails in one of a small number of ways: shrinkage porosity where the metal solidified last, inclusions carried in from the mould, and cracks from uneven cooling. All three are decided before any metal is poured.

Once the mould is packed, the options are gone. Simulation moves that decision point earlier, to where changing it costs nothing.

What CPSS Models

Casting Process Simulation System predicts how the metal fills the cavity and, more importantly, the order in which it solidifies. The last region to solidify is where shrinkage collects, and the objective is to place that region in a riser rather than in the part.

For a bowl liner or a grinding roller with heavy and light sections in one casting, that is not obvious by eye.

Then The Mould

After simulation, the sand moulds are made. The cavity is kept as solid and as clean as possible, because inclusions come from mould material breaking away during the pour — a clean cavity is the only defence.

Bottom-pouring ladles are used throughout, which fills the cavity from below rather than dropping metal through air where it can pick up oxide.

And Then Verification

• Raw materials for melting are purchased to a high standard, and temperature is controlled throughout the pour to achieve a fine grain structure.
• Samples are taken to verify the material analysis and adjusted if necessary. Inspected samples are retained for at least three years for traceability.
• Where the casting warrants it, ultrasonic testing, magnetic particle testing and dye penetrant inspection are carried out in our own laboratory.

Why It Matters To A Buyer

Simulation is invisible in the finished part, which is exactly the problem — a casting with internal porosity looks identical to a sound one until it fails.

The design tools behind it here are Solidworks and CAD, a 3D scanner for reverse engineering, and CPSS for the pour itself.