3 axis CNC milling is similar to conventional milling in that all movements are in 3 axis only (X, Y, Z, left-right, forward-backwards, up-down). Typically the angle of the head is fixed or cannot be moved in anything but the up and down(Z axis) direction automatically. All conventional milling processes such as end milling, slot milling, face milling, drilling, tapping, trepanning, chamfering and others are possible. Also possible is 3D contour milling and this feature is commonly used on a 3 axis milling machine for milling out mould and die cavities as undercuts are undesirable.
Three axis CNC milling machines are often available with tool changers and pallet changers for high volume production
In most instances when the CNC milling job requires undercuts and milling on multiple sides of the job, a 5 axis CNC milling machine is required(or 6 axis milling, or lathe/mill combo machines).
3 axis CNC milling machines can use a wide variety of cutting tools such as end mills, slot mills, bull nose cutters, ball nose cutters, drills, taps, thread milling cutters, boring heads, reamers, slitting saws, tee slot cutters, dovetail cutters, and even laser marking heads to peform a large variety of machining operations.