Lost foam casting (also called evaporative pattern casting) uses polystyrene foam patterns coated with refractory paint. The foam cluster is buried in dry binder-free sand. When molten metal is poured, the foam vaporises instantly, and the metal fills the cavity to form the casting.

Lost foam casting process
Create the foam pattern	Create the foam pattern: The pattern is made from pre-expanded polystyrene (EPS) that is heated in an aluminum die to expand and fuse the beads. The pattern can be carved, machined, or created using injection molding.
Coat the foam	A ceramic refractory coating is applied to the foam to protect it from the sand and create a barrier
Compact the sand	The foam pattern is placed in a flask and surrounded by unbonded sand, which is compacted using a vibration table.
Pour the metal	Pour the metal: Molten metal is poured into the flask, causing the foam to evaporate and leaving behind the metal
Remove the coating	Remove the coating: The refractory coating is removed to expose the metal part.
Surface treatment	Sandblasting and machine process.

✅ No parting lines or flash; no separate sand cores needed. It delivers great design freedom for complex geometries, internal passages and undercuts.

✅ Parts can be integrated into one casting, cutting assembly work. Less machining is required.

✅ Dry sand is recyclable; the workflow is simpler and cleaner than traditional sand casting.

✅ Suitable for both medium and large castings, competitive for mid-to-high volume runs.

⚠️ Foam pattern fabrication adds upfront cost for very small batches.

⚠️ Strict process control on coating, pouring and ventilation is required to avoid defects.

⚠️ Surface finish is not as fine as investment casting. It works best for ductile iron, grey iron, alloy steel and bronze.

Automotive manifolds, motor housings, gearbox housings, pump bodies, valve parts, agricultural machinery and hydraulic components.

We run a dedicated lost foam workshop and support custom parts from your drawings or samples. We offer CNC machining, heat treatment and surface finishing. Send us your requirement for a reliable quotation.