Trushape is a lost foam casting foundry in India making complex, single-piece castings from 3.5 to 90 kg (7.7 to 198 lb) in steel, iron, aluminium and other alloys, with no cores and no parting lines, held to ISO 8062-3 DCTG 11 to 14 and machined and tested under one roof for buyers across North America and Europe.
Lost foam casting, also called evaporative pattern casting (the Lost-Foam-Verfahren in German, moulage à mousse perdue in French), is a casting process in which molten metal is poured straight onto a foam pattern of the part, coated with a thin refractory layer and packed in loose, unbonded sand. The foam vaporises as the metal arrives and the metal takes its exact place, so complex parts are cast in one piece, with no cores and no parting line.
Trushape Precision Castings is an ISO 9001, ISO 14001, ISO 45001 and ISO 13485 certified lost foam casting foundry in Bhavnagar, Gujarat, India. We cast parts from 3.5 to 90 kg (7.7 to 198 lb) in carbon, low-alloy, stainless and tool steels, grey and ductile irons, and aluminium, copper, nickel and cobalt alloys, hold ISO 8062-3 DCTG 11 to 14, and heat-treat, CNC machine and test them under one roof for buyers across the United States, Canada, Mexico, the United Kingdom and the European Union.
Follow one manifold from polystyrene beads to a finished casting. The pattern becomes the mould, the foam becomes gas and the metal takes its place, all under one roof in Bhavnagar.
Polystyrene beads, about the size of grains of sugar, are heated with steam in a pre-expander. The blowing agent inside each bead boils, and the beads swell many times over into light, closed-cell foam, then rest to stabilise.
The beads are blown into a metal tool shaped like the part, plus its shrinkage allowance, and fused with steam into a solid foam pattern. For samples, patterns can instead be cut from foam block and glued in sections.
The pattern is glued to a foam sprue and pouring cup. Smaller patterns can share one sprue as a cluster, so several parts are cast in a single pour.
The cluster is dipped in a water-based ceramic slurry and dried. The thin coating becomes the mould surface: strong enough to hold the sand back, and permeable, so the gas from the foam can escape through it.
The coated cluster is stood in a flask and dry, unbonded sand is poured around it while the flask vibrates. The sand flows into every passage and packs tight, with no binder and no mould halves.
Molten metal from our induction furnaces is poured straight onto the foam. At the metal front the foam flashes to gas and escapes through the coating into the sand, and the metal takes its exact place. Each heat is checked by spectrometer.
Once the metal has solidified, the casting is lifted straight out of the loose sand, which simply runs off it: one of the cleanest shake-outs in the foundry. There is no mould to break, and the sand is cooled, screened and used again.
The sprue is cut off, then castings are shot blasted, heat-treated, CNC machined and inspected to your drawing, all in-house, so parts leave ready to assemble.
In lost foam there is no cavity to fill. The foam pattern stays in the sand until the metal reaches it, then vaporises, and the metal takes its place, passages and all. Drag the pour, pick a stage, or press play.
The coated foam pattern sits in a flask of loose, dry sand, compacted by vibration. There is no cavity: the foam fills the space the metal will take.
Lost foam casts in one piece what is often cut, bent, welded and bolted together. Switch between the two ways of making this example manifold, turn on X-ray to see the passages the foam forms, and drag to turn it.
An illustration of a typical conversion, counted from the parts shown. Whether an assembly can become one casting depends on its size, walls and alloy, and we review each drawing before we quote.
Lost foam casting typically holds ISO 8062-3 grades DCTG 11 to 14, with no parting line or core shift to add to them. Slide to your nominal dimension and pick a grade to see the total tolerance it allows as-cast.
| Nominal size (mm) | Nominal size (in) | DCTG 11 | DCTG 12 | DCTG 13 | DCTG 14 |
|---|---|---|---|---|---|
| Up to 10 | Up to 0.39 | 2.8 | 4.2 | n/a | n/a |
| 10 to 16 | 0.39 to 0.63 | 3.0 | 4.4 | n/a | n/a |
| 16 to 25 | 0.63 to 0.98 | 3.2 | 4.6 | 6.0 | 8.0 |
| 25 to 40 | 0.98 to 1.57 | 3.6 | 5.0 | 7.0 | 9.0 |
| 40 to 63 | 1.57 to 2.48 | 4.0 | 5.6 | 8.0 | 10.0 |
| 63 to 100 | 2.48 to 3.94 | 4.4 | 6.0 | 9.0 | 11.0 |
| 100 to 160 | 3.94 to 6.30 | 5.0 | 7.0 | 10.0 | 12.0 |
| 160 to 250 | 6.30 to 9.84 | 5.6 | 8.0 | 11.0 | 14.0 |
| 250 to 400 | 9.84 to 15.75 | 6.2 | 9.0 | 12.0 | 16.0 |
| 400 to 630 | 15.75 to 24.80 | 7.0 | 10.0 | 14.0 | 18.0 |
| 630 to 1,000 | 24.80 to 39.37 | 8.0 | 11.0 | 16.0 | 20.0 |
Total casting tolerance in millimetres to ISO 8062-3. When the tolerance is symmetric, half of it applies either side of the nominal dimension, so DCTG 12 at 100 to 160 mm means ±3.5 mm. n/a: ISO 8062-3 gives no general value for that grade at that size, so the dimension needs its own tolerance on the drawing. The grade for each part is agreed at drawing review, and tighter tolerances on critical features are reached by CNC machining.
Full ISO 8062-3 and VDG P690 tolerance tablesEvery route has a sweet spot. Pick a process to raise its profile in 3D and drag to turn the chart. The scores are relative and indicative; the right choice always depends on shape, size, volume, alloy and tolerance.
A foam pattern in loose, unbonded sand forms internal passages, undercuts and curves with no cores and no parting line, so assemblies become single castings and machining falls.
Chemically bonded sand sets at room temperature around a pattern, so tooling is simple and cheap, but passages need cores and the mould has a parting line. We run no-bake sand from 3 to 40 kg.
Moulds of sand bonded with clay and water are cheap and quick to make and suit very large castings, but surfaces are rougher and every passage needs a core. It is a common alternative we compare against, not a line we run.
A thin, rigid resin sand shell made on a heated metal pattern gives smoother, more accurate castings, with cores for passages and fast cycles for medium to high volumes.
A ceramic mould around an expendable wax pattern gives the finest detail and the tightest tolerances of any casting process, near net shape, in almost any alloy.
| Criterion | Lost foam | No-bake sand | Green sand | Shell molding | Investment casting |
|---|---|---|---|---|---|
| Typical tolerance | ISO 8062-3 DCTG 11 to 14 | DCTG 11 to 14 | Wide, depends on moulding method | DCTG 8 to 12 | CT5 to CT7 |
| Internal passages | Formed by the foam, no cores | Resin sand cores | Sand cores | Resin sand cores | Usually no cores; ceramic cores for deep passages |
| Mould parting line | None | Yes | Yes | Yes | None |
| Weight at Trushape | 3.5 to 90 kg | 3 to 40 kg | Not offered | 5 to 60 kg | 0.003 to 30 kg |
| Alloys | Almost any, except low-carbon grades | Most ferrous and non-ferrous | Most ferrous and non-ferrous | Carbon, low-alloy, stainless and tool steels, copper alloys | Almost any |
| Tooling | Foam pattern tool, moderate cost; none for patterns cut from block | Low | Low | Metal patterns, moderate cost | Moderate; none with 3D-printed patterns |
| Best volumes | Medium to high; samples from cut patterns | Low to medium | Low to very high | Medium to high | Prototypes to high volume |
Pick what your part needs most. The deck turns to the alloy we would start with, with ASTM and EN equivalents, relative ratings and the parts it usually goes into.
Need: Economical strength
Typical parts: brackets, housings, flanges and general engineering parts.
Economical and easy to machine, with good strength after normalising.
Need: High strength
Typical parts: levers, couplings, hydraulic bodies and drive parts.
Through-hardening strength, quenched and tempered in-house to your specification.
Need: Toughness under load
Typical parts: heavy-duty housings, off-highway and rail parts.
High strength with toughness in heavier sections, for parts that take shock loads.
Need: Hard wearing surface
Typical parts: wear plates, forming tools, liners and cutting edges.
A high-carbon, high-chromium steel that hardens right through for wear resistance.
Need: General corrosion
Typical parts: pump bodies, valve bodies, food and chemical parts.
The default choice for corrosion resistance. Low-carbon L grades are not advisable by lost foam, so we cast those by investment casting or shell molding.
Need: Hardness and corrosion
Typical parts: pump and valve wear parts.
Hardenable stainless for wear, with moderate corrosion resistance.
Need: Damping and machinability
Typical parts: gearbox and compressor housings, manifolds and motor frames.
Casts freely into thin, complex shapes, machines well and damps vibration.
Need: Strength with ductility
Typical parts: pump bodies, hydraulic manifolds, valve bodies and agricultural parts.
Spheroidal graphite gives toughness close to steel with the castability of iron.
Need: Light weight
Typical parts: intake manifolds, cylinder heads, housings and brackets.
Heat-treatable for strength at about a third of the weight of iron.
Need: Thin, pressure-tight walls
Typical parts: thin-walled housings, marine and pump parts.
A eutectic alloy with excellent fluidity for thin, pressure-tight walls.
A starting point for engineers comparing cast grades across North American and European specifications. Final selection always follows your drawing, service conditions and governing standard.
| Alloy family | Common grades | Equivalents | Why it is chosen | Typical parts |
|---|---|---|---|---|
| Carbon steel | EN8, C45 | AISI 1040, 1045; 1.0503 | Economical strength, easy machining | Brackets, housings, flanges |
| Chromium-molybdenum steel | 4140, 42CrMo4 | 1.7225, UNS G41400 | Through-hardening strength after quench and temper | Levers, couplings, hydraulic bodies |
| Nickel-chromium-molybdenum steel | 4340, EN24 | 34CrNiMo6, 1.6582 | Strength with toughness in heavy sections | Off-highway and rail parts |
| Austenitic stainless | 304, 316 (CF8, CF8M) | 1.4308, 1.4408 | Corrosion resistance and toughness | Pump and valve bodies, food and chemical parts |
| Martensitic stainless | 410 (CA15) | 1.4011, UNS J91150 | Hardness and wear with moderate corrosion resistance | Pump and valve wear parts |
| Grey cast iron | EN-GJL-250 (GG25) | ASTM A48 Class 35 to 40 | Castability, damping and machinability | Gearbox, compressor and motor housings |
| Ductile (SG) iron | EN-GJS-400-15 (GGG40) | ASTM A536 60-40-18 | Strength and ductility with iron's castability | Pump bodies, hydraulic manifolds, valve bodies |
| Aluminium-silicon-magnesium | LM25, A356 | EN AC-42000, EN AC-42100 | Light and heat-treatable | Intake manifolds, cylinder heads, housings |
| Aluminium-silicon | LM6 | EN AC-44100 type, A413.0 type | Fluidity for thin, pressure-tight walls | Thin-walled housings, marine parts |
| Tool steel | D2 | 1.2379 (X153CrMoV12) | Wear resistance and hardness | Wear plates, forming tools, liners |
| Copper alloys | C95800, C83600 | CC333G (nickel aluminium bronze), CC491K (LG2 gunmetal) | Seawater corrosion and wear resistance | Pump and valve parts, bearings, marine fittings |
| Nickel and cobalt alloys | M35-1 (Monel 400), Stellite 6 | UNS N24135, UNS R30006 | Corrosion, heat and wear resistance | Valve trim, pump parts, wear parts |
Equivalents are the closest common matches, shown for comparison. We cast to the ASTM, EN, ISO or customer specification on your drawing and verify the chemistry of every heat by spectrometer.
See all 50+ alloy gradesIn 1958 a patent showed that metal poured onto a foam pattern makes the foam vanish and takes its exact place. We still cast the same way. Only now the foam is moulded to shape, the sand is loose and vibrated, and every part comes out in one piece, from 3.5 to 90 kg, in steel, iron and aluminium.
A lost foam casting is only as good as the pour behind it. We check what matters on site: the chemistry of every heat, the soundness of critical sections and every critical dimension against your drawing.
Every heat checked on Spectromaxx and Bruker spectrometers against your grade, carbon included.
Mechanical properties tested to your material specification.
Internal soundness of critical sections, to the acceptance level you specify.
Internal flaws and wall thickness in heavier sections.
Surface and near-surface flaws on steels and irons.
Surface-breaking cracks and porosity on stainless, aluminium and other non-magnetic alloys.
Dimensional reports on profiles, bores and datums against your drawing.
Leak and pressure checks on manifolds, pump bodies and valve bodies where your plan requires them.
One record from melt to dispatch, ready for your incoming inspection and your customers' audits. Material certificates are issued to EN 10204 3.1 as standard, and to 3.2 when your order calls for independent inspection.
Good castings start on the drawing board. These are the guidelines our engineers use when they review a new lost foam part. Hover or tap a card to turn it over.
Consolidation. Draw the part as one piece. Tubes, brackets, flanges and bosses that are now welded or bolted together can often be cast as a single lost foam casting.
Passages. The foam forms internal passages, but coating must drain from them and sand must fill them. Give each passage an opening wide enough, and we check it at design review.
Walls. Even walls let the metal front advance steadily as the foam vaporises. Blend thick to thin gradually so heavy sections can feed without shrinkage.
Corners. Generous fillets help the metal flow and the sand pack around the pattern. Sharp internal corners concentrate stress and can trap gas.
Draft. Nothing is drawn out of the sand, so walls need no mould draft. Only moulded foam patterns need a slight draft to leave their tool.
Tolerances. Lost foam holds ISO 8062-3 DCTG 11 to 14. Mark functional features and datums, add stock only where you need it, and we machine the few that need more.
Samples. For samples and small batches, patterns can be cut from foam block and glued in sections, so the first castings need no pattern tool.
Alloy. The foam can add carbon as it vaporises, so low-carbon and carbon-critical grades such as 316L are not advisable by lost foam. Name the grade at enquiry and we route those parts to investment casting or shell molding.
We work to the iron, steel, aluminium, tolerance and inspection standards common on North American and European drawings, and to your own specification and inspection plan.
Trushape holds ISO 9001, ISO 14001, ISO 45001 and ISO 13485. We do not hold IATF 16949 or ASME approvals, so automotive, pressure-equipment and code parts are cast to your drawing, specification and inspection plan, and product approvals stay with you. We support them with samples, test data and full records. PED certification is in process.
Download our certificatesAn export-focused foundry with a dedicated export desk, already shipping castings to Germany, the UK, Belgium, Denmark, Spain and Italy. Pick a region to trace the lane from Bhavnagar.
Vehicle, engine, pump and agricultural equipment makers across Michigan, Wisconsin, Illinois and Ohio.
Vehicle, rail and machinery builders around Toronto, Windsor and Montreal.
Nearshore automotive and heavy-equipment assemblers in Coahuila and Nuevo León that need machined castings on schedule.
Engineering, pump and off-highway equipment makers across the Midlands and the North.
Automotive, drivetrain and machinery suppliers in Baden-Württemberg and Lower Saxony.
Pump, valve and machinery makers in Belgium, the Netherlands and France.
Vehicle and equipment makers in Sweden, and automotive suppliers in Piedmont.
Series parts travel by sea freight in export packing, and urgent samples by air. Delivery terms and documentation are agreed with our export desk for each order, and every shipment carries English certificates and reports.
Drag the ring or let it turn. Each part family is a classic lost foam shape, with the alloys we typically use for castings from 3.5 to 90 kg (7.7 to 198 lb).
AlloysLM25, A356
IndustryAutomotive and engines
Curved runners cast in one piece, without cores.
AlloysDuctile iron
IndustryEngines
Thin, even walls that follow the gas path.
AlloysAluminium, grey iron
IndustryEngines and compressors
Water and oil passages formed by the foam.
AlloysDuctile iron, CF8M
IndustryPumps and water
Volutes and passages with no core shift.
AlloysGrey and ductile iron, CF8M
IndustryFlow control
Seats, bores and flanges machined in-house.
AlloysDuctile iron, carbon steel
IndustryHydraulics
Cast passages in place of drilled and plugged cross-holes.
AlloysGrey iron, aluminium
IndustryMachinery and vehicles
Bearing bores and faces machined to drawing.
AlloysGrey iron, aluminium
IndustryAir and refrigeration
Pressure-tight walls, tested on request.
AlloysDuctile iron, carbon steel
IndustryAgriculture
Tough parts for hard-working equipment.
AlloysDuctile iron, 4340
IndustryRailway
Shock-loaded parts with full test records.
AlloysCF8M, LM6
IndustryMarine
Corrosion-resistant bodies for seawater service.
AlloysGrey iron, aluminium
IndustryElectrical machines
Repeatable geometry for series machining.
Buyers in North America and Europe move lost foam work to us for the same six reasons.
Pattern, cluster, melt, heat treatment, CNC machining, finishing and testing in one 100,000 sq ft facility, which cuts lead times by 30 to 40%.
IntegratedLost foam, investment casting, shell molding, no-bake sand and gravity die casting under one roof, so every part gets the route that suits its shape, size and volume.
6 processesSteels, grey and ductile irons, and aluminium, copper, nickel and cobalt alloys, melted in induction furnaces and verified by spectrometer every heat. Only low-carbon grades go to another route.
50+ gradesISO 8062-3 DCTG 11 to 14 as-cast with no parting line or core shift, critical features machined, and every critical dimension verified on a Zeiss CMM.
DCTG 11 to 14ISO 9001, 14001, 45001 and 13485 systems, in-house NDT and an EN 10204 3.1 certificate with every batch.
Audit readyA dedicated export desk, English documentation and export packing for sea or air freight, plus a proven China-plus-one option.
NA and EuropeFrom a 1950s American patent to the process that cast a carmaker's engines, and on to iron and steel parts of every kind.
H.F. Shroyer filed a patent in 1956, granted in 1958, for casting metal on a foam pattern packed in bonded sand. The foam vaporised and the metal took its place.
The process was adapted to loose, unbonded sand compacted around the coated pattern. That is the lost foam casting used today, and it makes shake-out effortless.
Automotive research turned lost foam into a production process for aluminium engine parts, removing cores and machining operations.
General Motors' Saturn plant in Spring Hill, Tennessee, began casting aluminium engine blocks and cylinder heads by lost foam.
Better foams, coatings and automated cluster assembly carried the process into iron and steel, and into pump, valve, hydraulic and heavy equipment castings.
Trushape casts lost foam parts from 3.5 to 90 kg in steel, iron, aluminium and other alloys, then machines and inspects them under one roof.
Lost foam casting, also called evaporative pattern casting, is a casting process in which molten metal is poured straight onto a foam pattern of the part, coated with a thin refractory layer and packed in loose, unbonded sand. The foam vaporises as the metal arrives, and the metal takes its exact place. In German it is the Lost-Foam-Verfahren and in French moulage à mousse perdue.
Polystyrene beads are pre-expanded with steam and moulded into a foam pattern of the part. The pattern is glued to a foam sprue and pouring cup, dipped in a permeable refractory coating and dried. It is then set in a flask, surrounded by dry unbonded sand compacted by vibration, and molten metal is poured onto it. The foam vaporises, the metal solidifies in its place, and the sand pours away at shake-out.
Lost foam casting makes complex, single-piece parts that would otherwise need cores or be assembled from several pieces, such as intake and exhaust manifolds, cylinder heads, pump housings, valve bodies, hydraulic manifolds and compressor and gearbox housings. At Trushape it covers castings from 3.5 to 90 kg (7.7 to 198 lb).
Design freedom comes first: internal passages, undercuts and curved channels are formed by the foam pattern itself, with no cores and no parting line. Several parts of an assembly can be combined into one casting, the unbonded sand needs no binder and is reused, and castings come out close to their final shape, so machining, welding and assembly work fall.
No. The foam pattern already contains every internal passage. The sand packed inside the coated passages holds their shape while the foam vaporises and the metal fills around it. With no separate cores there is no core making, no core setting and no core shift. Passages only need openings wide enough for the coating to drain and the sand to fill.
Lost foam casting typically holds ISO 8062-3 grades DCTG 11 to 14, depending on size, geometry and alloy. For a 100 to 160 mm (3.9 to 6.3 in) dimension that is a total tolerance of 5 to 12 mm, or ±2.5 to ±6 mm. With no parting line and no cores there is no mismatch or core shift to add to it, and critical features are machined on our CNC machines.
Our lost foam line casts parts from 3.5 to 90 kg (7.7 to 198 lb), the heaviest range of our six casting processes. Smaller, more intricate parts from 0.003 kg move to investment casting, so one supplier covers everything from a few grams to 90 kg.
Almost any alloy we cast: carbon steels such as EN8 and C45, low-alloy steels such as 4140 and 4340, stainless steels such as 304, 316 and 410 (CF8, CF8M and CA15), tool steels, grey and ductile irons such as EN-GJL-250 and EN-GJS-400-15, aluminium alloys such as LM25, A356 and LM6, and copper, nickel and cobalt alloys. The exception is low-carbon and carbon-critical grades such as 316L, which we cast by investment casting or shell molding instead.
Standard stainless grades such as 304, 316 and 410 (CF8, CF8M and CA15) can be. Low-carbon and carbon-critical grades such as 316L and 304L (CF3M and CF3) are not advisable by lost foam, because the vaporising foam can add carbon to the metal. For those grades we recommend investment casting or shell molding instead.
Both use an expendable pattern, but lost foam pours metal straight onto a foam pattern in loose sand, while investment casting melts a wax pattern out of a ceramic shell before pouring. Lost foam suits larger, heavier parts from 3.5 to 90 kg (7.7 to 198 lb) at DCTG 11 to 14, and investment casting smaller, finer parts from 0.003 to 30 kg (0.1 oz to 66 lb) at CT5 to CT7.
American engineer H.F. Shroyer filed the first patent for casting metal on a foam pattern in 1956, granted in 1958. His full mold process packed the pattern in bonded sand. In 1964 the process was adapted to loose, unbonded sand, which is the lost foam casting used today, and in 1990 General Motors' Saturn plant began casting aluminium engine blocks and cylinder heads this way.
Yes. Trushape exports castings to Germany, the UK, Belgium, Denmark, Spain and Italy and serves buyers across North America and Europe, including the United States, Canada and Mexico. Parts ship by sea or air freight with English documentation, and delivery terms are agreed per order.
The foam vanishes and the part remains, in one piece, with its passages formed and no cores to set. Trushape casts, heat-treats, machines and verifies lost foam parts under one roof for manufacturers across North America and Europe.