Formulae
Milling Formulas - INCH Values
Symbol
Description
Formula
SFM
Surface Feet / Minute
RPM × D
SFM = __________
3.82
RPM
Revolutions / Minute
SFM × 3.82
RPM = __________
D
IPT
Feed / Tooth
IPM
IPT = _______
z x RPM
IPM
Inches / Minute
D(eff)
Effective Diameter
IPM = IPT × RPM × z
D(eff) = 2 ×
R2- (R - D1)2
Deff
Symbol key:
D = tool diameter (in.)
z = no. of flutes
R = radius
D1 = DOC (ap)
Milling Formulas - METRIC Values
Description
Formula
Vc
Surface Meters / Minute
π×D×n
Vc = __________
1000
n
Revolutions / Minute
Vc × 1000
n = __________
π×D
fz
Feed / Tooth
Vf
Millimeters / Minute
D(eff)
Effective Diameter
TECHNICAL
SECTION
Symbol
vf
fz = _____
n×z
vf = (n) × (z) × (fz)
D(eff) = 2 ×
D × ap - ap2
Deff
Symbol key:
π = 3.1416
D = tool diameter (mm)
z = no. of flutes
ap = depth of cut
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