Mill Turning
A mill turn, or multitasking machine, commonly refers to a machine that is capable of both milling and turning operations that can include the use of live tooling. A typical mill turn configuration has multiple axes which, as a minimum include an x, y and c-axis. These allow for milling operations along the length of the part as well as traditional OD and ID lathe turning operations.
Types of mill turn machine
The axes that characterise mill turn machines are described in detail below:
X-axis – This refers to the movement perpendicular to the axis of the stock, this is the normal lathe cutting axis.
Z-axis – This refers to movement along the axis of the stock, it is used when holes are drilled into the centre of the stock, and is also one of the traditional lathe axes.
C-axis – This refers to movement around the axis of the stock. This axis is the same axis as the spindle, however during milling operations the main spindle drive is typically disengaged and a servo drives the c-axis to allow for accurate positioning. A c-axis allows for slots to be cut into the part and results in angled walls and curved bottoms.
Y-Axis – This refers to movement perpendicular to the axis of the stock with a live tool or separate milling head, and works in conjunction with the c-axis to mill slots and flat features into the part. Y-axis machining results in slots with straight sides and flat bottoms.
A mill turn has a turret tooling setup which allows for the inclusion of both stationary tools as well as live tools for milling operations. This is the key way in which a traditional lathe differs from a mill turn machine.
More advanced machines can have a sub spindle, multiple tool turrets and a separate milling head with a b-axis that lets the tool rotate in relation to the axis of the stock. These advanced mill turn machines can approach the efficiency of automatic turning lathes.
