Castora Foam Tech runs two distinct casting technologies under one roof: Lost Foam Casting, built for high-volume structural components, and Replica Investment Casting, built for complex, high-precision parts. Each is suited to a different class of requirement.
Send us your drawing and our engineering team will evaluate it and recommend the right process — you don't need to know which one you need before you talk to us.
Lost Foam Casting (LFC) is a precision casting process where an expendable EPS pattern is coated and embedded in unbonded sand. When molten metal is poured, the foam is replaced by metal — producing a near-net-shape casting with no sand cores, no parting lines, and no draft angles. This is why Lost Foam is our process of choice for high-volume structural components like ISO container corner fittings.
Raw EPS beads are pre-expanded to controlled density, then steam-moulded into the exact shape of the corner casting. Our EPS shape moulding machines produce patterns with a cycle time of 5–6 minutes each. The foam pattern is a precise replica of the final metal casting — every aperture, wall thickness, and radius is built into the foam.
Individual foam patterns are glued into casting bunches — clusters arranged to maximise metal yield per box. Our CNC gluing machine ensures precise, repeatable assembly with minimal dimensional variation between batches. Target bunch weight is 125 kg minimum per 1×1×1 m box.
Each assembled pattern cluster is dipped in ceramic slurry — a refractory coating that creates a rigid barrier between the foam and the sand. The coating prevents sand infiltration into the casting surface, directly controlling final surface finish. Coated patterns are dried in our temperature-controlled drying rooms before proceeding.
Coated pattern clusters are placed in our steel mould boxes (1×1×1 m) and surrounded by unbonded silica sand. The boxes are placed on our 3D compaction table which vibrates the sand to achieve uniform, dense packing around every surface of the pattern — critical for dimensional accuracy. Each box holds 7 corner casting patterns.
Our 500KW induction furnace melts steel/iron charge material to the precise temperature required (1,500°C+). Chemistry is verified via spectro analysis before each pour. Liquid metal is poured into the mould box — the EPS foam instantly vaporises and is replaced by metal. Each heat produces 6.16 MT of liquid metal, supporting our 10-heat-per-day production target.
After solidification, boxes are tilted at our hydraulic box tilting station and the casting cluster is separated from sand. Our 20 TPH VLFP sand plant reclaims 98% of the sand — cooling it, removing magnetic particles, screening out fines, and returning it to the mould boxes. A closed-loop system that minimises waste and cost.
Each casting goes through fettling (removal of gates, risers, surface cleaning), followed by dimensional inspection, hardness testing, and visual QC. Accepted castings are shot blasted, primer coated, and packed for dispatch. Full batch documentation — heat records, spectro report, dimensional check — accompanies every order.
| Parameter | Lost Foam (Castora) | Conventional Sand Casting |
|---|---|---|
| Surface Finish | Excellent — smooth, ready for coating | Rough — requires heavy finishing |
| Dimensional Accuracy | High — near-net-shape | Lower — shrinkage and draft variation |
| Sand Cores Required | None — foam is the core | Yes — complex, time-consuming |
| Design Flexibility | High — complex geometry possible | Limited by parting line & draft angles |
| Production Volume | High — automated, consistent | Moderate — labour intensive |
| Material Waste | Minimal — 98% sand reclamation | Higher — cores discarded after use |
Replica Investment Casting (the "lost-wax" process) starts with a wax replica of the component, built up into a ceramic shell mould. Once the wax is melted out and the shell fired, metal is poured directly into the cavity it leaves behind — producing complex geometry, fine detail, and a superior as-cast surface finish that's difficult to achieve any other way. It's our process of choice for smaller, intricate, high-tolerance components.
Molten wax is injected into a precision aluminium or steel die, producing an exact wax replica of the finished component — the "replica" that gives the process its name. Every fillet, boss, and internal feature is captured in the wax at this stage.
Individual wax replicas are attached to a central wax sprue and runner system, forming a "tree" of components arranged to maximise yield per shell and give molten metal a clean path into every cavity.
The wax tree is repeatedly dipped in ceramic slurry and stuccoed with refractory sand, building up a multi-layer shell mould around the wax. Each layer is fully dried before the next is applied.
The finished shell is flash-heated in a steam autoclave, melting the wax out and leaving behind a hollow ceramic mould that is a precise negative of the original replica.
The empty ceramic shell is fired at high temperature to burn out any residual wax and gain strength, then filled with molten metal at controlled temperature while still hot — improving fill and dimensional accuracy.
Once solidified, the ceramic shell is broken away, individual parts are cut from the tree, then ground, shot blasted, and dimensionally inspected before dispatch.
A quick guide — or just send your drawing and let our engineering team decide for you.
| If your component needs… | Lost Foam Casting | Replica Investment Casting |
|---|---|---|
| Larger, heavier structural parts | Best fit | Typically not required |
| Small-to-medium, intricate geometry | Possible | Best fit |
| High-volume, cost-efficient production | Best fit | Suited to precision runs |
| Finest as-cast surface finish | Excellent | Best fit |
| Tight dimensional tolerances on detail features | High accuracy | Best fit |
| Not sure yet | Send your drawing — we'll recommend the process | |