Lost Foam Casting Manufacturer
A near-net-shape process using evaporative foam patterns — no draft angles, no cores, no parting lines. Ideal for large, complex iron and aluminum parts that traditional sand casting cannot achieve economically. Proven in large-scale tooling and mold frames since 2005.
Sample Lead Time
Primary Materials
Mold Frames & Tooling
Featured Exhibitor
Mold frames, tooling & structural castings
Complex undercuts & internal cavities
Both materials from one factory
30 days for production orders
EVAPORATIVE PATTERN
Lost foam casting mold frame — cast aluminum, ~200 kg · Photo placeholder
“Lost foam casting uses an expendable polystyrene (EPS) foam pattern coated in refractory slurry and embedded in loose unbonded sand. When molten metal is poured, the foam vaporizes — leaving a precise metal replica of the original shape.”
Unlike conventional sand casting, there is no binder in the sand, no parting line, and no need for cores to form internal cavities. The EPS foam pattern — machined or molded to exact dimensions — is consumed during pouring, producing a near-net-shape casting in a single step.
At Renyi Castings, we have used lost foam as our primary method for producing large tooling and mold frames internally since our founding. This real production experience — not just foundry theory — is why international buyers from Germany, the United States, and Europe trust us with their most demanding large-part requirements.
No Binder Sand
No Draft Angles
No Cores Needed
Near-Net Shape
Cast Aluminum
Ductile Iron
Large Parts Welcome
GIFA 2019 Exhibitor
Lost foam unlocks shapes and cost structures that conventional sand casting and investment casting cannot match — especially at large part sizes.
No parting line, no draft angle, no core box. Complex internal passages, undercuts, and large hollow sections are cast in a single pour. Part complexity is limited by foam pattern design — not by mold assembly constraints.
From multi-ton mold frames for automotive lightweight components to crusher frames and large industrial housings — lost foam scales to sizes where investment casting is impractical and sand casting struggles with dimensional control.
Compared to investment (lost wax) casting, lost foam requires no ceramic shell building, no wax injection tooling, and no autoclave dewaxing. For large and medium parts, this translates to significantly lower per-unit and tooling costs.
Tight dimensional tolerances reduce machining stock and post-processing requirements. Smooth as-cast surfaces minimize secondary operations — resulting in shorter lead times and lower total cost of ownership for the buyer.
| Material Family | Grades Available | Typical Application |
|---|---|---|
| Cast Aluminum | A356, A380, AlSi9Mg, AlSi12 | Mold frames, automotive structural, lightweight housings |
| Ductile Iron | QT400-18, QT500-7, QT600-3, QT700-2 | Large mold frames, machine tool bases, industrial frames |
| Gray Iron | HT200, HT250, HT300 | Wheels, housings, counterweights, structural components |
| Wear-Resistant Iron | White iron (420 Brinell), Ni-Hard | Crusher liners, mill parts, aggregate equipment |
| High Manganese Steel | Gx120Mn13 (Hadfield) | Crusher hammers, jaw plates, impact-wear parts |
Note: Lost foam is best suited to cast iron, ductile iron, and aluminum alloys. For carbon steel, stainless steel, or high-alloy steels in complex geometries, investment casting is usually the appropriate process.
Part Weight Range
Typical Dimensional Tolerance
As-Cast Surface Roughness
Internal Cavities / Undercuts
Seven controlled steps — from EPS foam pattern to finished casting — with process parameters monitored at each stage for consistent quality.
01
Expanded polystyrene (EPS) foam is cut, molded, or assembled into the precise shape of the final part
02
Multiple foam segments are bonded together with foam glue for complex geometries; gating and risering system attached
03
Foam pattern dipped or brushed in refractory slurry — creates a rigid shell that controls surface finish and gas permeability
04
Coated pattern placed in flask and surrounded by fine unbonded silica sand under vibration — no binder, no moisture issues
05
Molten metal poured into the pattern — foam vaporizes and escapes through the coating; metal fills the void in real time
06
Part solidifies in the sand; after cooling, the unbonded sand is poured out — no shakeout hammer required
07
Gates removed, surface cleaned, dimensional check and NDT performed; machining and surface treatment per drawing
Renyi Castings has supplied large lost foam castings to automotive tooling suppliers and industrial equipment OEMs in Germany and the US — parts where size, dimensional stability, and material integrity are non-negotiable.
Mold frames in cast aluminum and ductile iron for automotive lightweight component tooling (supplied to Koller Group, Germany)
Consistent quality across repeat orders — same dimensional and surface finish standards batch to batch
Competitive pricing on large castings where Western foundries cannot match China’s cost structure
In-house use of lost foam for our own large tooling — real process ownership, not outsourced capability
Both cast aluminum (Al-Si alloys) and ductile iron (QT series) produced in the same foundry
Sample Lead Time
Production Lead Time
Hall 12, Stand B39
Choose the right process for your part. Lost foam occupies a unique position — better geometry than sand casting, lower cost than investment casting, and purpose-built for medium-to-large part sizes.
| Criteria | Lost Foam THIS PAGE | Sand Casting | Investment Casting | Gravity Die Casting |
|---|---|---|---|---|
| Part Size Range | 0.5 kg – 5,000 kg | Grams – 10+ tons | Grams – ~50 kg | 0.1 – 50 kg |
| Internal Cavities / Cores | No cores needed | Core boxes required | Wax core possible | Very limited |
| Draft Angles Required | None | Yes — 1°–3° | Minimal (0.5°–1°) | Yes — 2°–5° |
| Dimensional Accuracy | ±1.0–1.5 mm (CT7–8) | ±2–4 mm (CT9–11) | ±0.1–0.3 mm (CT4–6) | ±0.3–0.8 mm (CT6–7) |
| Surface Finish (as-cast) | Ra 6–12 µm | Ra 12–25 µm | Ra 1.6–3.2 µm | Ra 3.2–6.3 µm |
| Primary Materials | Cast iron, Ductile iron, Aluminum | Iron, Steel, Al, Brass, Bronze | Steel, Stainless, Al, Brass, Bronze | Aluminum, Brass, Bronze |
| Tooling Cost | Low (EPS pattern) | Low (wood/resin pattern) | Medium (injection mold) | High (steel die) |
| Unit Cost at Low Volume | Low | Low | Medium | High |
| Best For | Large, complex iron & Al parts; no-core internal channels; prototype to mid-volume | Very large parts; diverse materials; simple-to-moderate shapes | Small, high-precision parts; complex alloys; tight tolerances | Medium Al/brass parts; good surface; moderate volumes |
Not sure if lost foam is right for your part? Our team can recommend the optimal process — or combine multiple processes across a single assembly.
The most versatile casting process — iron, aluminum, brass, and steel from grams to 10+ tons. Automated and manual moulding lines with in-house tooling.
High-precision parts in stainless steel, alloy steel, brass, and bronze. Tolerances to ±0.08 mm. Best for small-to-medium complex components.
Precision wax pattern casting for small, intricate shapes in steel, stainless, and brass. Achieves superior surface detail vs. lost foam for smaller parts.
Reusable permanent molds for aluminum and brass parts — excellent surface finish and dimensional consistency for medium-volume production.
Lost foam castings from Renyi are used where large, dimensionally stable, complex metal parts are needed — across tooling, heavy industry, mining, and infrastructure.
– Press tool mold frames (Al & ductile iron)
– Die casting tool bases
– Lightweight component tooling
– Fixture plates & jig bodies
– Forming die housings
– Crusher hammers (Mn13 steel)
– Jaw plates & impact bars
– Feeder wear liners
– Washer drum components
– Aggregate equipment aftermarket parts
– Machine tool bases & columns
– Large pump housings
– Gearbox cases (complex internal channels)
– Counter weights & ballast blocks
– Compressor cylinder blocks
– Cast iron wheel assemblies
– Valve bodies & manifolds (large bore)
– Bracket & structural frames
– Railway components
– Marine & offshore hardware
Lost foam is best suited for parts weighing 0.5 kg to several tons. It excels at medium-to-large complex parts where sand casting cannot achieve the required internal geometry and investment casting is cost-prohibitive due to part size. Very small, highly precise parts are better served by investment (lost wax) casting.
Yes. We regularly produce both cast aluminum alloys (AlSi9Mg, A356, A380) and ductile / gray iron (QT series, HT series) using the lost foam process. Both material families can be produced from the same foam pattern tooling — ideal for customers evaluating material options before final specification.
Sample (first article) lead time: 15 working days from approved drawings and foam pattern. Production order lead time: 30 days. For urgent projects, expedited timelines can be discussed. RFQ feedback is returned within 12 hours; full quotation within 48 hours.
Lost foam is primarily used for cast iron and aluminum — these are the materials where the process delivers the best technical and cost results. For carbon steel, stainless steel, and high-alloy steels requiring tight tolerances, we recommend ourInvestment Castingprocess instead, which handles a broader range of ferrous and non-ferrous alloys.
Renyi Castings is certified to ISO 9001 and IATF 16949. All shipments are accompanied by dimensional inspection reports and material test certificates. NDT options (UT, MT, PT, X-ray) are available upon request. We supply to automotive-tier and industrial OEM buyers who audit our quality system directly.
Send your 2D / 3D drawings, material grade, required weight range, and target annual volume. Our engineering team will assess process suitability and return a full quotation — including DFM notes on foam pattern design — within 12–48 hours.
Process recommendation — lost foam vs. sand vs. investment
DFM review on foam pattern design & gating
Tooling cost + unit price quoted separately
Machining, heat treatment & surface treatment options
NDT & material certification options included
Send drawings (STEP / DXF / PDF) to RFQ@renyicastings.com — response within 12 hours. Sample delivery in 15 days.