Rapid Prototyping China vs US Cost

Picking the wrong process for a prototype is the fastest way to blow your budget and schedule. The right one can cut spend by double digits and keep your build moving. This guide shows mid-level product engineers how to choose and combine CNC, 3D printing, vacuum casting, and soft-tool injection molding to lower total cost—plus what to expect when comparing rapid prototyping China vs US cost.

Key takeaways

• Start with your gating constraint (precision, cosmetics, volume, or time) and let that pick the process. Switch as the constraint changes.

• Use 3D printing to explore and learn; validate function with CNC; bridge cosmetic pilots with vacuum casting; drop unit cost at 100–5,000 units with rapid aluminum tooling.

• Tight tolerances and premium finishes are silent cost multipliers—reserve them for functional and visible faces only.

• Expect faster lead options and lower tooling/labor costs in China; plan for shipping, duties, and inspection to compare apples-to-apples with US suppliers.

• Write RFQs that fix material, tolerances, cosmetic faces, volume, inspection level, and delivery terms; request two process options to reveal crossovers.

Quick process decision matrix

Choose by the primary constraint first; then refine with DFM and finish choices.

How to choose the right process fast

CNC machining (metals and engineering plastics)

• Use when precision, material properties, or threaded features are the gating factor. Standard CNC tolerances of about ±0.005 in. (metals) and ±0.010 in. (plastics) are commonly achievable; tighter specs add machine and inspection time, which increases cost. According to Xometry’s manufacturing standards, tightening beyond defaults drives up cycle time and QA effort, raising spend as a result; see the details in the Xometry community’s guidance on tolerances of machined parts (2025). 

• Caution: Fine internal radii and deep pockets may require smaller tools and slower feeds. Where possible, add reliefs, increase radii, or split the part to avoid long, fragile end mills.

3D printing (SLA/SLS/FDM)

• Use when the priority is speed and design learning. Major services commonly offer same‑day to 3‑day options for small runs; broader windows run 1–7 days depending on process and quantity, as summarized in Protolabs’ process selection guide (2025) and updates. 

• Caution: Parts that must mimic molded cosmetics or production plastics usually need a later step (vacuum casting or molding). Expect tradeoffs in anisotropy and surface texture.

Vacuum (urethane) casting

• Use for 10–100 molded‑like plastic parts without paying for metal tooling. Silicone molds are inexpensive and quick compared to aluminum or steel tools. Guides from RapidDirect and Fictiv describe typical silicone mold costs in the hundreds to low thousands of dollars and short lead times for small batches.

• Caution: Silicone mold life is limited; complex geometries and high‑gloss finishes reduce part‑per‑mold yield. Plan additional molds for larger runs.

Rapid (aluminum) injection molding

• Use when volumes reach 100–5,000+ parts and consistency matters. Aluminum tooling can be produced quickly; Protolabs explains why aluminum is effective for short‑run molding and how it compresses schedules. 

• Caution: Upfront tool cost dominates early; verify that volume and stability justify the spend. If scope is uncertain, start with vacuum casting and switch when the forecast firms up.

Typical lead times you can plan around

The bands below aggregate published service windows. Your exact geometry, queue position, and finish will shift the numbers.

DFM moves that cut cost without risk

Tolerance strategy

• Start with standard tolerances (e.g., ±0.005 in. metals; ±0.010 in. plastics) and tighten only where function requires. Tighter callouts force slower machining and more inspection time. Xometry’s guidance (2025) explains these tradeoffs in plain terms; use that as your internal baseline before RFQs.

Surface and finish strategy

• Define cosmetic faces explicitly. For CNC plastics/metals, request “as‑machined + bead blast” on non‑cosmetic areas and upgrade only where visible. For anodizing or powder coating, remember masking and curing add schedule and cost. 

Geometry choices

• Favor generous internal radii, consistent wall thickness, and drafted walls when molding is likely. Avoid awkward undercuts unless absolutely necessary—slides and lifters translate into tooling complexity and money. For a concise refresher, see the practical design guidelines maintained by Kaierwo (neutral reference): Kaierwo design guidelines.

Hybrid workflows that lower total cost

A proven path is: 3D print to learn quickly → CNC for functional prototypes → vacuum cast for 10–100 cosmetically representative units → rapid aluminum tooling for 100–5,000+.

• When deciding between vacuum casting vs injection molding for the bridge step, compare schedule and expected part count. Kaierwo’s neutral explainer on vacuum casting vs injection molding for low-volume production outlines where each shines: Vacuum casting vs injection molding (Kaierwo blog).

• If your forecast solidifies beyond ~100–300 units and the design stabilizes, explore rapid tooling programs. A short overview of options is available here: Rapid tooling at Kaierwo.

Rapid prototyping China vs US cost signals

You’ll often see lower labor/tooling costs and denser capacity in China, while US suppliers may offer day‑one proximity, simpler logistics, and easier onsite collaboration. To make a fair comparison, normalize:

• Lead time: Quote production + finishing + transit. DHL and UPS publish 2–5 business‑day express services China→US for 1–5 kg prototype shipments (service‑level dependent). 

• Inspection: Specify inspection level (e.g., 100% on critical dimensions; AQL on others) and whether you need measurement reports. This avoids hidden cost deltas.

• IP and data handling: Confirm NDAs, file‑handling procedures, and who owns fixtures and tools.

RFQ fields to lock down for apples‑to‑apples

• Material and grade, target tolerances, cosmetic faces and finish, quantity by build (e.g., 10/50/100), required inspection, and delivery terms (Incoterms, destination ZIP). Ask for two process options when you’re near a crossover (e.g., vacuum casting vs rapid tooling) to reveal the true minimum.

Micro example: 50 cosmetic housings via vacuum casting (COI)

A team needed 50 ABS‑like cosmetic housings for a pilot demo with molded appearance but no time or budget for metal tooling. 

They supplied STEP files with clearly marked cosmetic faces. At a China‑based service like Kaierwo, the workflow was: 

1) 3D print a high‑resolution master, 

2) build silicone molds, 

3) cast urethane parts in an ABS‑like resin, 

4) bead‑blast and paint only visible faces. Lead time landed within the typical ~5–15 day band for vacuum casting. 

The team skipped aluminum tooling until demand firmed above a few hundred units. By deferring tooling and limiting premium finishes to visible areas, they contained spend and met the schedule.

For background on CNC and materials capabilities that often complement this path, see: CNC machining at Kaierwo.

FAQ

Q:How many times should I mention the primary keyword in my RFQ or documentation?

A:None. Keywords are for search. In technical documents, focus on specifications and constraints. Use precise material/tolerance/finish language so suppliers can quote accurately.

Q:Where is the crossover between vacuum casting and rapid injection molding?

A:It depends on geometry, finish, and expected revisions. Many teams start with vacuum casting for 10–100 units and move to aluminum tooling once demand stabilizes and unit economics matter. Compare both in your RFQ when you’re near that boundary.

Q:Can I hold ±0.001 in. everywhere on a CNC prototype?

A:You can attempt it, but it will be expensive and slow. Instead, assign that tolerance only to critical features. Keep most dimensions at standard levels to control machining and inspection time.