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 such as blocks, brackets, housings and 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, with fewer setups, better accuracy and shorter lead time. Milltech runs mill-turn and sub-spindle turning centres for exactly these parts.
