Force needed for milling:

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.

The force needed for milling a workpiece might be determined if the particular cutting pressure (p) (that means force (in kg) needed per square millimeter of chip cross-section being removed) is known. Specific cutting pressure based not only on the workpiece material but also on the maximum thickness of the chip being eliminated from the workpiece. Force (F = F_c) required throughout milling a workpiece is specified by

F_c = p A (kg)                                               --------------- (1)

Here, A is the area of cross-section of the chip. To evaluate the maximum force (F_max) acting throughout milling, A must be replaced by A_max (maximum cross-sectional area of the chip)

F_max = p A_max  (kg)                                         ------------ (2)

Usually the ratio of F_max and F lies between 1.2 to 1.8.

If the cutting and force speed are known, the power might be calculated by using following equation.

HP =    (metric)                                   ---------- (3)

Here, V (= V_c) is the cutting speed in m/min. To compute maximum power needed, replace F_c by F_max.

 From above discussion, this is not possible to determine the specific cutting pressure unless   A_max is known. To find out A_max, two cases might be analyzed: face milling and plain milling.