CNC machining and metal parts: MOQ, tooling, lead time and landed cost
Confidence 4/5 Established practice
CNC machining has no tooling cost, which makes it the right answer for prototypes, low volumes and geometry that will still change. The trade-off is a high unit cost that falls slowly with volume, so for anything above a few hundred units it is worth comparing against casting or moulding — and it is worth saying plainly that at 200 units, machining a part can easily cost more per unit than a mould would cost in total.
Quick answers
| Minimum order quantity | One piece. This is the genuinely no-minimum process: there is no set-up tool, only programming and fixturing time. |
| Lead time | One-off or small batch: 5–10 days. Repeat production batches: 10–20 days. |
| Tooling | No mould. Programming and fixturing are charged per order, typically USD 0–150 depending on complexity. |
| Unit cost | Roughly USD 8–80 per part at quantities of 10–100 for a small to medium part, dominated by machine time and material. At 1,000+ units, casting or moulding usually wins. |
| HS classification | Depends entirely on the material and function: 7326.90 for other iron or steel articles, 7616.99 for other aluminium articles, 8466 for machine parts and accessories. Machined parts cannot be classified from the drawing alone. |
| Certification | Material certificates matter more than certifications here. Ask for the mill certificate for the specific heat or batch, especially for 304/316 stainless and for any structural application. |
| Duty | Section 232 tariffs on steel and aluminium derivatives have applied to some machined goods in the US, which means a simple HS code lookup can understate the true duty. This category needs a tariff check at quote time rather than a rate from memory. |
Common mistakes
- Specifying a tolerance the part does not need. Tightening from ±0.1 mm to ±0.02 mm can multiply cost.
- Asking for "stainless steel" without a grade. 304 and 316 differ in corrosion performance and price.
- Surface finish defined only by adjective. Ra values or a physical sample are needed.
- Ignoring deburring and passivation, which are separate operations and often quoted separately.
- Assuming a machining quote scales linearly to volume; it does not, and the crossover to casting arrives sooner than expected.
Detailed answers
Sources
- CNC machining cost drivers and volume crossover — Industry practice; consistent with published machining service pricing
- Iron and steel article classification — World Customs Organization HS nomenclature
- Section 232 steel and aluminium derivative tariffs — US Department of Commerce
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