Rapid Prototyping Guide: CNC, 3D Printing, Vacuum Casting for Chinese Prototyping Shops

Prototyping Methods Overview

Prototyping Method | Materials | Min Qt | Lead Time | Cost Range

--- | --- | --- | --- | ---

CNC Machining | Aluminum, steel, plastic | 1 | 2-5 days | ¥200-2000/piece

SLA (Resin 3D Print) | Photosensitive resin | 1 | 1-2 days | ¥50-500/piece

SLS (Nylon 3D Print) | Nylon PA12, TPU | 1 | 2-3 days | ¥100-800/piece

FDM (Filament Print) | PLA, ABS, PETG | 1 | 1-3 days | ¥30-200/piece

Vacuum Casting | PU resin (RTV) | 10-50 | 5-8 days | ¥80-300/piece

Most Chinese prototyping shops offer free DFM (Design for Manufacturing) feedback within 24 hours.

Choosing the Right Method

1. CNC Machining: Best for functional metal prototypes that match production material

2. SLA: Best for appearance models with smooth surface finish (Ra 0.4μm)

3. SLS: Best for functional plastic parts that need strength and flexibility

4. FDM: Best for quick concept models where appearance is secondary

5. Vacuum Casting: Best for 10-50 pieces in simulated production material

How Chinese Prototyping Shops Work

Most shops in Shenzhen, Dongguan, and Shanghai accept 3D files (STEP, STP, STL) via WeChat or email.

Typical process:

Day 1: Send file → Receive quote within 4 hours

Day 2-3: Production begins

Day 4: Photos/video of finished parts sent for approval

Day 5: Parts shipped (DHL/FedEx 3-5 days to US/Europe)

Tip: Request an 'urgency fee' for 24-hour turnaround (50-100% premium, widely available in Shenzhen).

Cost Saving Tips

1. Combine multiple parts into one STL file to reduce setup cost

2. Use FDM for first iteration, CNC for final (save 60% on design iterations)

3. Avoid sharp internal corners — add fillets (R≥1mm) to reduce machining time

4. For vacuum casting, keep wall thickness 1.5-3mm for best results

5. Most Chinese shops offer a 10-20% discount on repeat orders