A mill-turn machine combines turning and milling in one platform: it spins the part like a lathe but also has a milling spindle (and often a B-axis and sub-spindle) so it can cut off-center holes, flats, slots and complex 3D features without moving the part to a second machine.
Doing everything in one setup — 'done-in-one' — eliminates re-fixturing errors and cuts lead time, which is why mill-turn is favored for complex, high-value parts.
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