Milling and turning are the two core CNC processes, and choosing the right one — or both — decides how a part is made. Here is how each works and which your component needs.
How does CNC milling work?
In milling, the workpiece is held stationary and a rotating cutting tool removes material, moving across multiple axes (3, 4 or 5). Because the tool can approach from many directions, milling suits prismatic parts — blocks, brackets, housings, plates — as well as pockets, slots, holes and complex 3D geometry. Milltech's milling cell runs 3, 4 and continuous 5-axis machines, holding tolerances as tight as ±0.005 mm.
How does CNC turning work?
In turning, the relationship is reversed — the workpiece rotates at speed against a fixed cutting tool. This makes turning the natural choice for cylindrical, axially symmetric parts: shafts, bushes, pins, spindles, fittings and bar-fed components. Turning holds fine tolerances — down to ±0.005 mm where required — and produces excellent surface finishes on round features.
Which process does your part need?
A simple rule of thumb:
- Round and symmetric → turning.
- Prismatic or complex geometry → milling.
- Both features on one part → mill-turn (below).
Most real components are not purely one or the other — a turned shaft may need milled flats, keyways or cross-drilled holes.
What is mill-turn, and when do you need it?
Mill-turn machines combine turning and milling in one setup, often with a sub-spindle that machines the back face too. That means a part with both turned and milled features is completed in a single operation — fewer setups, better accuracy and shorter lead time. Milltech runs mill-turn and sub-spindle turning centres for exactly these parts.
