For many machine shop people, the B-axis turn-mill platform is the first that comes to mind when they think of “multitasking machines” that often can complete parts in one setup. But, while that equipment most closely resembles a lathe, are they lathes or mills? The answer is: both. It’s this five-axis platform in particular whereby the line between mill and lathe is most blurred.
When referencing the “B-axis,” we’re talking about the rotation of the turn-mill’s milling head that enables the head to perform work from various angles on the side or end of a part held in a main or subspindle. This is shown in the photo above for an application that, ironically, calls for no turning work (a rotor for an automotive supercharger). In fact, five-axis capability thanks to the B-axis opens up the opportunity to process fully prismatic parts from barstock, billets, castings or forgings as well as machine contoured parts like, the rotor shown above, or even turbine blades. Plus, some turn-mill models can perform gear hobbing and skiving or be fitted with additive-manufacturing laser cladding units for repair work of large parts or the addition of small features to large parts.
The video below shows common operations a turn-mill can perform. In this case, an Integrex i-100ST machine with subspindle from Mazak demonstrates pinch turning as well as other simultaneous turning and milling operations on both the main and subspindle.
These machines can also use the B-axis milling spindle to perform “turning milling,” in which instead of feeding a static, single-point turning tool down the Z-axis, a spinning milling tool is moved down the part to “turn” the diameter.
Read more: Turn-Mills: Being About the B-Axis