5 axis CNC machining is a CNC milling machine that is firstly capable of using the conventional 3 axis - x, y and z (left-right, forward-backwards, up-down), but has an additional 2 axis of movement in the ability for both the table and the head to swivel. This allows the head and table to be moved around as the other axis are being fed allowing undercuts to be machined and allowing machining on multiple faces of the work piece.
A variation on the 5 axis CNC machine is the 4 axis CNC milling machine which has a swiveling table or a rotary chuck, but the head can only move up and down.
The five axis CNC machining allows 3D contours to be machined along with conventional milling processes such as slot milling, face milling, end milling, drilling, tapping, chamfering, and trepanning.
5 axis milling can be used for most conventional milling processes involving basic geometry typically machined in 3 axis, but can be used to finish mill components requiring undercuts, or features milled onto multiple faces of the workpiece. 5 axis machining can often be used to produce low quantities of parts which are normally die-cast cost effectively.
Most 5 axis CNC machining can be programmed offline, directly from 3D CAD data making this a flexible, cost effective, versatile manufacturing process.