From 3-axis milling to 5-axis simultaneous machining
In their simplest design, milling machines are set up for 3-axis machining: the tool moves over the workpiece in the X, Y and Z direction. A rotary axis, in the headstock or the table for example, extends the range of machining because components can also be positioned at an angle. But this is only a precursor to 5-axis milling, which machine tool manufacturers achieve by means of a second rotary axis. This makes it possible to align the workpiece in almost any position, so that it can be machined from five sides in one clamping process, which makes it possible to produce metal components with complex geometries too. The workpiece only needs re-clamping if you intend to machine a sixth side.
The king of milling disciplines – 5-axis simultaneous machining – is a further development of 5-axis technology: in this process, all the axes are interpolated, which gives the milling machine the maximum machining versatility. The kinematics of the CNC machine is usually housed in a swivel-type indexing table, which continuously moves the component as the milling tool cuts away the material. An alternative to this is head kinematics. Here the milling head has two rotary axes which allow it to move freely around the workpiece. 5-axis simultaneous milling makes it possible to produce so-called free-form surfaces, which are common in mould construction, for example.