Mill-Turn Cost Drivers

Machine Rates

Mill-turn machines (Okuma MULTUS, DMG Mori NTX, Mazak Integrex class) run $150–$250/hour depending on the machine size and shop. Compare this to $85–$125/hour for a standard CNC lathe and $75–$125/hour for a standard VMC. The rate premium is 25–75% over a single conventional machine.

The Setup Math

Consider a part that requires turning on a lathe (1 setup), then milling on a VMC (1 setup). Each setup costs 30–60 minutes including fixturing, indicating, and first-article inspection. That's 1–2 hours of non-cutting time. On mill-turn, it's one setup — 30–45 minutes. You save 30–75 minutes of setup time per batch.

At a $150/hour mill-turn rate, you're paying roughly the same for total machine time but getting tighter tolerances and faster delivery. The breakeven point is typically at 5–20 parts — below that, the setup savings don't offset the higher rate. Above that, mill-turn wins on both cost and quality.

What Drives Cost Up

Complex milling content. Heavy milling on a mill-turn is slower than on a dedicated mill. Parts with significant milling — deep pockets, large face areas — take longer.

Sub-spindle work. Back-face operations through sub-spindle transfer add cycle time for the transfer itself and for the additional machining.

Exotic materials. Same as any machining — titanium, Inconel, and hardened steels cost more in tool wear and cycle time.

What Drives Cost Down

Eliminating the second machine. No VMC setup, no fixture, no inter-operation handling. One machine, one operator, one setup.

Quantity. Setup and programming are fixed. Per-part cost drops rapidly with volume.

Providing a STEP file. CAM programming from a solid model is faster than working from drawings.