How to Cast Metal Parts from 3D Prints

5 December 2025

How to Cast Metal Parts from 3D Prints

Shanghai Casting & Foundry Expo (CSFE), 2-4 December 2025, made one point unmistakably clear: additive manufacturing (AM) is no longer a visitor in the foundry—it is a co-worker. Below is a concise status report for overseas customers who buy iron, steel or ADI castings and wonder whether AM can, or should, replace conventional casting.

1. What We Saw on the Show Floor

-Several companies showcased 1.5-meter workbox-style 3D printers that can produce silica or ceramic molds with an accuracy of ±0.3 millimeters within 36 hours.

- A Chinese OEM demonstrated a 4 t hydraulic valve body: printed sand core + green-sand jacket—casting delivered in 72 h, machining time cut by 85 %.

- Several service booths offered SLA resin patterns for investment casting; 80 µm layer thickness and <0.05 % ash make them suitable for titanium and steel grades.

2. Benefits Confirmed by Our Own Trial Runs

Benefit	Quantified Result	Comment
Pattern-less start-up	Tooling cost –90 %	No wooden or metal patterns needed
Lead-time	1-3 days vs 2-4 weeks	Critical for prototype and small series (<100 pcs)
Geometric freedom	0.5° draft possible	Internal channels cast to near-net shape
Inventory	Zero pattern storage	Digital file replaces physical stock

3. Limitations Still Relevant in 2025

Parameter	AM Boundary	Casting Boundary
Maximum size	4 m × 2 m × 1 m (sand) 0.5 m³ (metal powder)	15 m × 6 m × 3 m
Single piece weight	<10 t (sand) <150 kg (SLM)	200 t+
Surface as-cast	Ra 12-25 µm	Ra 25-50 µm
Cost at 1 000+ pcs	2-3× higher than hard-tool casting	Economies of scale achieved
Energy & powder	High electricity; powder 30-50 USD/kg	Sand 0.05 USD/kg

4. Impact on Conventional Foundries

- Pattern shops are being converted into AM cells; skilled wood pattern makers retrained as CAD/MAGMA operators.

- Gating and risering design now starts in voxel space; simulation software links print parameters to solidification models.

- Small-batch and aftermarket orders migrate to printed cores/moulds, freeing hard-tool capacity for high-volume work.

- Quality documentation moves from "pattern card" to "layer-wise build report" – traceability actually improves.

5. Can AM Completely Replace Casting?

Short answer: No.

- World cast-metal output ≈110 million t/y; powder-bed AM metals ≈0.3 million t/y—0.27 % market share.

- Above ±150 kg or 2 m, AM cycle time and residual stress make it uncompetitive.

- Many grades (large ADI modules, low-alloy wear plates, heavy manganese steel) still rely on furnace metallurgy and sand casting for property and cost reasons.

6. Recommended Hybrid Roadmap

1. Prototype & pilot run (1-100 pcs) → 3D printed sand or investment pattern

2. Pre-production (100-1 000 pcs) → Printed core + conventional mould line

3. Serial production (>1 000 pcs) → Machine metal hard-tool; keep printed inserts for complex water jackets or oil galleries

4. Repair / re-engineering → Printed wax or sand for local geometry upgrades without new pattern cost

7. Next Steps

At SMEMACH, our specialty is ADI Casting, and we primarily use 3D printing to create models. Additive manufacturing is not a threat to casting processes; it's a new tool that makes casting faster, smarter, and more competitive. If you are interested in this topic, please contact us.

How to Cast Metal Parts from 3D Prints – Complete 2025 Guide

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