Page 198 - Mechanical Engineer's Data Handbook

186 MECHANICAL ENGINEER'S DATA HANDBOOK
2.4.2 Milling parameters

Power for peripheral milling

Symbols used:
P = power (watts)
u = cutting speed (m s- ')
z=number of teeth
b=chip width (mm)
C = constant
f=feed per tooth (mm)
d = depth of cut (mm)
r = radius of cutter (mm)
x, y = indices
k =constant

Values of x, y, k and C are given in the tables.
Material X Y k

Steels 0.85 0.925 0.164
Cast iron 0.70 0.85 0.169

Material C*
~~
Free machining carbon steel 980 (120 BHN) 1190 (180 BHN)
Carbon steels 1620 (125 BHN) 2240 (225 BHN)
Nickekhrome steels 1460 (125 BHN) 2200 (270 BHN)
Nickel-molybdenum and
chrome-molybdenum steels 1600 (150 BHN) 1960 (280 BHN)
Chrome-Vanadium steels 1820 (1 70 BHN) 2380 (190 BHN)
Flake graphite cast iron 635 (100 BHN) 1330 (263 BHN)
Nodular cast irons 11 10 (annealed) 1240 (as cast)
*BHN numbers are hardness grades.

Milling cutting speeds

Let :
D =cutter diameter (mm),
N = number of revolutions per minute.
Cutting speed v=nDN/1000(mmin-')