Down milling:

In case of down milling, workpiece is fed to the cutter in the similar direction in which the cutter is rotating. Now, the cutting force keeps the workpiece pressed down against the machine table. Furthermore, the risk of chatter is also low.

The net force throughout milling is made up of two components as explained in earlier section on single-point cutting.

(A) Force needed for plastic deformation of the workpiece to form the chips, and

(B) Force needed to overcome friction among the face and chip of the tooth of the milling cutter, and among the cutter and workpiece.