The CNC Batch-Size Cost Curve — How Quantity Drives 60% of Your Quote
Quantity is the single largest cost lever in CNC machining, and it's the one most buyers control least. This piece shows what the cost curve actually looks like and where the inflection points are.
The shape of the curve
For a representative aluminum 6061 bracket, EU workshop pricing in Q2 2026:
| Quantity | €/part | % of 1-unit cost |
|---|---|---|
| 1 | €145 | 100% |
| 5 | €62 | 43% |
| 10 | €38 | 26% |
| 25 | €26 | 18% |
| 50 | €22 | 15% |
| 100 | €18 | 12% |
| 250 | €15 | 10% |
| 500 | €13 | 9% |
| 1000 | €11 | 8% |
The curve is steep in the 1–25 range, flattens around 50–100 units, and becomes nearly horizontal beyond 500.
Why the curve looks like this
Three fixed costs get amortized over the batch:
- CAM programming: 1–3 hours at €60–€100/hour per setup. Amortizes linearly.
- First-article inspection: ~30 minutes CMM time. Same for 1 or 10,000 parts.
- Setup and fixturing: 1–4 hours per unique operation. Same regardless of batch.
For a typical 3-operation part with 2 hours of programming and 90 minutes of setup, fixed cost is ~€300. Spread over 1 unit that's €300/part. Spread over 100 units that's €3/part.
The per-part variable cost (actual machining + material) is roughly €10–€15 for our bracket. So the curve asymptotes around €13/part in the 500+ range.
The four useful inflection points
These are the batch sizes where pricing changes qualitatively:
Quantity 1 — prototype pricing
Workshops price single-piece jobs with a "prototype surcharge" reflecting the overhead of a one-off. This is genuinely fair pricing; don't expect to negotiate it down.
Quantity 10 — "batch one" pricing
Below 10 units, each additional part is dramatic. Above 10, the curve bends. Most workshops have a de facto 10-unit breakpoint for discount.
Quantity 50 — "production" pricing
Workshops treat 50+ units as production runs and often apply a 15–20% discount vs their 10-unit quote rate. If you can bundle orders to hit this threshold, do it.
Quantity 500 — "volume" pricing
Above 500, workshops sometimes switch to a different operational model (dedicated shift, multi-machine, tool-specific fixturing). Price drops another 10–15%.
Practical batching strategies for small teams
Most hardware startups buy in quantities too small to capture these economies. Three fixes:
- Annual forecast batching: place one order per year for 12 months of forecast, staggered release. Workshop holds inventory, you get volume pricing.
- Design-reuse batching: if your Rev-2 product uses the same bracket as Rev-1, order both generations together.
- Cross-product consolidation: if Product A and Product B share brackets, combine their POs.
These three tactics typically compress unit cost by 20–30% without changing design.
What affects the curve besides quantity
- Tolerance class: see Aluminum 6061 tolerance cost tradeoffs
- Surface finish: see Aluminum 6061 surface finish guide
- Material: stainless is steeper than aluminum
- Lead time: rush jobs flatten the curve (less batch discount available)
See your own curve
The Quote Configurator lets you drag the quantity slider and watch the curve in real time for your specific material and process. Works without signup.
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