RAPID METAL CASTING SERVICES

Tooling-Free Metal CastingFor Prototypes and Production

Unionfab, a China-based metal casting company, combines 3D printed patterns, sand molds, cores, investment casting routes, CNC machining, and finishing to deliver metal cast parts faster than traditional tooling-based casting.

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No MOQ • ISO 27001 Certified • Free DFM Analysis

Excellent4.7 out of 5

FLEXIBILITY

NO MOQ

Prototype and scale seamlessly without volume commitments or setup barriers.

FACTORY AREA

80,000m²

The combined area of all Unionfab facilities totals 80,000m²

LEAD TIME

2 DAYS

Fast-turn production with simple parts ready in as fast as 2 DAYS.

CERTIFIED

ISO

ISO 9001, 14001, 13485 & IATF 16949 certified with NDA-secured manufacturing workflows.

Why Choose Unionfab's Rapid Metal Casting Service?

Mold-Free Rapid Turnaround

Bypass lengthy tooling phases with 3D-printed mold patterns. By combining SLA and 3D sand printing with rapid casting, we deliver sand castings in 1-3 weeks and investment castings in 2-4 weeks. Accelerate your time-to-market.

Optimized for Low Volume

The ultimate cost-effective solution for batches of 1 to 500. Avoid unamortized tooling costs and premium CNC fees. We deliver maximum ROI for your small-batch production runs.

Unrestricted Design Freedom

Break free from CNC toolpath limits and traditional draft angles. Seamlessly produce complex near-net parts, intricate internal cooling channels, and lightweight lattices directly from your CAD design.

One-Stop Flexible Manufacturing

Stop juggling multiple vendors. We integrate Rapid Casting, CNC machining, and Metal 3D Printing to intelligently match the optimal process for your specific material, geometry, and volume.

Years of Experience

Countries Covered

0M+

Parts Made

Customer Served

Four Technology Routes

Choose the right casting route based on part size, geometry, tolerance requirements, quantity, and production intent.

Rapid Sand Casting

For large functional metal parts where CNC from billet is too expensive.

1-500 pcs1-3 weeksLarge parts

Surface Finish:
Tooling Cost:
Max Part Size:: 1800 x 1000 x 700 mm
Minimum Wall Thickness:: 5 mm
Best For:: Large housings, brackets, pump bodies, covers, bases, and thick-wall structural parts.

Rapid Investment Casting

For smaller metal parts with complex shapes, thin walls, fine details, or better surface needs.

1-200 pcs2-4 weeksSmall-medium parts

Surface Finish:
Tooling Cost:
Max Part Size:: 600 x 600 x 600 mm
Minimum Wall Thickness:: 2 mm
Best For:: Complex brackets, impellers, small housings, and parts with curves, ribs, or fine features.

Die Casting

For stable thin-wall metal parts with growing or repeat demand.

500-100k pcs4-8 weeksTooling required

Surface Finish:
Tooling Cost:
Best For:: Aluminum, zinc, or magnesium housings, covers, enclosures, handles, consumer hardware, automotive parts, and repeat-production components.

Metal Casting + CNC Finishing

A hybrid route for parts that need cast geometry and machined accuracy in key functional areas.

5-500 pcs3-5 weeksCast + CNCCritical tolerance

Surface Finish:: /(machined)
Tooling Cost:
Best For:: Parts with bearing seats, threaded holes, sealing faces, flat datum surfaces, shaft interfaces, alignment features, or assembly-critical area

*For surface finish, more stars mean better as-cast quality. For tooling cost, more stars mean higher upfront cost.

Rapid Metal Casting Materials

.Different casting routes fit different metal families. Start with material compatibility first, then choose the route by part size, geometry, quantity, tolerance, and timeline.

Large common casting alloys

Best for functional castings where size, structure, and cost matter more than fine surface detail.

Aluminum alloysCast ironCast steelBronze / brass

Best user signal:large size + functional structure + cost sensitivity.

Less ideal for:Small stainless precision parts, thin-wall aluminum, or high-detail surfaces.

Explore Our Full Material Library

Metal Casting Parts Made by Unionfab

Explore Our Product Showroom

Technical Specifications of Rapid Metal Casting

Values below are for early route selection only. As-cast tolerance, surface finish, size range, and minimum wall thickness all depend on alloy, geometry, casting orientation, and post-machining requirements.

	Rapid Sand Casting	Rapid Investment Casting	Die Casting
As-Cast Tolerance / Surface	±0.5–1.5 mm / Ra 6.3–25 μm. Typical as-cast reference for functional blanks.	±0.1–0.3 mm / Ra 1.6–6.3 μm. Typical as-cast reference for smaller detailed parts.	±0.1–0.2 mm / Ra 0.8–3.2 μm Typical as-cast reference after stable tooling.
ISO 8062 Reference Grade	CT7–CT12 3D-printed mold: CT7–CT9; conventional sand: CT9–CT12.	CT4–CT6 Typical rapid investment casting reference.	CT4–CT6 Typical pressure die casting reference.
Typical Size Range	50–1500 mm Best fit for medium to large castings.	10–400 mm Best fit for compact parts with fine details.	10–600 mm Best fit for stable thin-wall non-ferrous parts.
Minimum Wall Thickness	Al ≥4 mm / Steel & iron ≥5 mm Thicker walls are preferred for larger structural castings.	≥1.5 mm Thin walls depend on alloy flow, geometry, and shell design.	Al ≥1.5 mm / Zn ≥0.8 mm Draft, ribs, and gate design affect final wall feasibility.

Rapid Sand Casting

Rapid Investment Casting

Die Casting

As-Cast Tolerance / Surface

±0.5–1.5 mm / Ra 6.3–25 μm.

Typical as-cast reference for functional blanks.

±0.1–0.3 mm / Ra 1.6–6.3 μm.

Typical as-cast reference for smaller detailed parts.

±0.1–0.2 mm / Ra 0.8–3.2 μm

Typical as-cast reference after stable tooling.

ISO 8062 Reference Grade

CT7–CT12

3D-printed mold: CT7–CT9; conventional sand: CT9–CT12.

CT4–CT6

Typical rapid investment casting reference.

CT4–CT6

Typical pressure die casting reference.

Typical Size Range

50–1500 mm

Best fit for medium to large castings.

10–400 mm

Best fit for compact parts with fine details.

10–600 mm

Best fit for stable thin-wall non-ferrous parts.

Minimum Wall Thickness

Al ≥4 mm / Steel & iron ≥5 mm

Thicker walls are preferred for larger structural castings.

≥1.5 mm

Thin walls depend on alloy flow, geometry, and shell design.

Al ≥1.5 mm / Zn ≥0.8 mm

Draft, ribs, and gate design affect final wall feasibility.

Post-Processing Options for Rapid Metal Casting

Enhance cast metal parts with heat treatment, precision machining, and protective finishing options selected for final performance requirements.

Heat Treatment

Strengthening internal metallurgy for reliability in extreme environments.

Key Processes:T6 Treatment (Aluminum), Solution Annealing (Stainless Steel), Stress Relief Annealing.

Benefits:Eliminates residual stress while drastically improving yield strength, hardness, and overall component lifespan.

Explore All Finishing Options

Design Best Practices for Rapid Metal Casting

Good casting results start before production. Unionfab reviews geometry, alloy, critical features, and post-processing needs early to plan the right casting route.

Keep wall thickness consistent

Large wall-thickness changes can increase shrinkage, porosity, distortion, and uneven cooling. Use gradual transitions where possible.

Add radii to internal corners

Fillets improve metal flow, reduce stress concentration, and make the part easier to cast and finish.

Mark critical dimensions

Use casting for near-net-shape geometry. Mark tight tolerances, flatness, sealing faces, bearing fits, threads, and precision holes for CNC machining.

Avoid isolated heavy sections

Thick isolated areas can cool unevenly and increase shrinkage risk. Balance material distribution where possible.

Identify internal channels and undercuts

Internal cavities, deep pockets, and undercuts may require cores, special mold design, or another manufacturing route.

Rapid Metal Casting vs. CNC Machining vs. Metal 3D Printing

Rapid Metal Casting

Cast-like geometryLower batch cost

Best For: Medium-to-large metal parts, cast-like geometry, and lower cost for small-to-medium batches.

Watch Out: As-cast tolerance is not CNC tolerance. Machine critical faces if precision is required.

CNC Machining

Precision first

Best For: Tight tolerance, clean interfaces, flat surfaces, threads, bores, or one-off precision parts.

Watch Out: Cost rises fast when most of the billet must be removed.

Metal 3D Printing

Complex geometry

Best For: Internal channels, lattice structures, topology-optimized geometry, or low-volume complex metal parts.

Watch Out: Build size, powder cost, and as-built surface finish can limit suitability.

Metal 3D printed titanium aerospace part

For more details of the three processes, check out our guide: How to Choose the Best Manufacturing Process for Custom Metal Parts

Quality Assurance & Inspection

We adhere to a strict multi-stage inspection protocol to ensure every part meets your exact specifications.

Coordinate measuring machine for inspection

Full FAI Documentation:

Every order includes a First Article Inspection report (upon request).

Precision Metrology:

We utilize state-of-the-art CMM (Coordinate Measuring Machines), profilometers for surface roughness, and calibrated hand tools.

Traceability:

All material certifications and heat treatment reports are archived and available for audit.

Standards Compliance:

Our quality systems are aligned with international ISO 9001 standards, covering dimensional, geometric (GD&T), and material requirements.

For more details on our quality standards, check out our Inspection Checklist (including both standard and premium options).

FAQs About Rapid Metal Casting

Choose rapid metal casting for functional metal parts, complex cast shapes, larger sizes, or low-volume production without traditional tooling. Choose CNC machining for simple geometries, tight tolerances, threads, holes, and precision surfaces. Choose metal 3D printing for highly complex designs, internal channels, lattices, lightweight structures, or very low quantities.

Yes. This is common. Casting creates the near-net-shape metal body, while CNC machining is used for critical dimensions, sealing surfaces, bearing fits, mounting holes, threads, and assembly interfaces.

Casting tolerance depends on process, alloy, part size, geometry, and mold strategy. Tighter tolerances are usually achieved by CNC machining critical features after casting.

A 3D CAD file is usually enough to start a manufacturability review, but a 2D drawing is strongly recommended if the part has critical dimensions, tolerances, threads, surface finish requirements, heat treatment, or inspection requirements.

No MOQ. Rapid metal casting can support prototypes and low-volume production.