CNC Machining vs Injection Molding: Cost Break-Even Analysis & When to Switch (2026)
CNC Machining vs Injection Molding: Cost Break-Even Analysis & When to Switch (2026)
The golden rule: CNC machining wins for quantities under 250–500 pieces. Injection molding wins for quantities over 5,000–10,000 pieces. Between 500 and 5,000, the decision depends on part complexity, material, and whether you can amortize the mold cost. A typical aluminum injection mold costs $3,000–15,000, while CNC has zero tooling cost — this is the fundamental economic trade-off.
Head-to-Head Comparison
| Factor | CNC Machining | Injection Molding |
|---|---|---|
| Tooling cost | $0 | $3,000–100,000 |
| Per-part cost (low volume) | $15–200 | $0.50–5 (after mold amortized) |
| Setup time | 1–3 days | 4–12 weeks (mold fabrication) |
| Material options | Metals + plastics | Plastics only (thermoplastics) |
| Design changes | Easy — modify program | Expensive — modify or remake mold |
| Surface finish | As-machined or post-processed | Mold texture determines finish |
| Tolerances | ±0.01–0.05mm | ±0.05–0.2mm (varies by material) |
| Lead time (first parts) | 3–15 days | 4–12 weeks |
Break-Even Analysis: When Molding Becomes Cheaper
| Part Type | CNC Cost/pc | Mold Cost | Molding Cost/pc | Break-Even Qty |
|---|---|---|---|---|
| Small ABS housing (20g) | $15 | $5,000 | $0.80 | ~350 pcs |
| Medium nylon gear (50g) | $28 | $8,000 | $1.50 | ~300 pcs |
| Large PP enclosure (200g) | $55 | $15,000 | $3.00 | ~290 pcs |
| Small PC lens (5g) | $22 | $12,000 | $0.50 | ~560 pcs |
| PEEK medical part (10g) | $65 | $25,000 | $8.00 | ~440 pcs |
Total Cost Over Volume: A Concrete Example
| Quantity | CNC Total | Injection Molding Total | Winner |
|---|---|---|---|
| 50 pcs | $1,400 | $5,040 (mold + parts) | CNC (72% less) |
| 250 pcs | $7,000 | $5,200 | Molding (26% less) |
| 500 pcs | $14,000 | $5,400 | Molding (61% less) |
| 5,000 pcs | $140,000 | $9,000 | Molding (94% less) |
| 50,000 pcs | $1,400,000 | $45,000 | Molding (97% less) |
The Hybrid Strategy: CNC for Prototype, Molding for Production
The optimal path for most plastic products: CNC machine 5–20 prototypes for design validation and market testing (2 weeks, $500–2,000), then invest in an injection mold once the design is proven and volume justifies it (4–8 weeks, $5,000+). This minimizes upfront risk while maximizing per-unit economics at scale.
More Process & Technology Guides
- CNC Machining vs 3D Printing Cost Comparison 2026: When Each Process Wins
- 5-Axis CNC Machining Guide: When It’s Worth the Cost vs 3-Axis (2026)
- CNC Turning vs CNC Milling: Which Process Does Your Part Need? (2026 Comparison)
- CNC Machining vs Metal Casting vs Forging: Process Selection Guide with Cost Data (2026)
CNC Precision Tech — China CNC machining sourcing and export support partner.