Technical Guidance The Basics of Milling
■ Parts
Body diameter
Boss diameter
Bore Dia. Keyway Width
Body
External cutting edge (Approach Angle)
Keyway Depth
Axial Rake Angle
Cutting edge angle
Ring
N
Reference ring
Cutting edge Inclination angle
True Rake Angle
Face relief angle
Fastener Bolt
A
Cutting edge indexable Insert
Chip pocket
Flank Relief Angle
Cutter Diameter (Nominal Diameter)
Locator
Clamp Plate
Enlarged Portion A
Reference ring
Face Cutting Edge Angle
External cutting edge (principal cutting edge)
Face cutting edge (Wiper Flat)
Radial Rake Angle
Chamfered corner
■ Milling Calculation Formulas
● Calculating Cutting Speed (Inch)
Work Material
Milling Cutters
SFM = 0.262 × DC × n
v c : Cutting speed (SFM) X : π ≈3.14
n
3.82 × SFM DC
v f
n =
DC : Nominal cutting diameter (inch) n : Rotation speed (min -1 ) (RPM) v f : Feed rate per minute (inch/min) f z : Feed rate per tooth (inch/t)
n
● Calculating Feed Rate (Inch) v f = IPR × n
v f
IPR =
n
v f
f z
● Calculating power requirements
● Relation between feed rate, work material and specific cutting force
Q × k c
a e × a p × v f × k c 60 × 10 6 × V
Symbol
P c =
=
Work Material Alloy Steel Carbon Steel Cast Iron Aluminum Alloy (1) 1.8 0.8 200 Q (2) 1.4 0.6 160 Q (3) 1.0 0.4 120 Q Figures in table indicate these characteristics. · Alloy steel and carbon steel: Traverse
60 × 10 3 × V
No.
10.000
P c : Power consumption (kw) H : Required horsepower (HP) Q : Chip evacuation amount (cm 3 /min) a e : Cutting width (mm) v f : Feed rate per minute (mm/min) a p : Depth of cut (mm) k c : Cutting force (MPa) Rough values Steel: 2,500 to 3,000MPa Cast iron: 1,500MPa Aluminum: 800MPa V : Machine efficiency (about 0.75) ( )
8.000
● Horsepower requirements
rupture strength σ B (GPa) · Cast iron: Hardness HB
P c 0.75
H =
6.000
(1)
4.000
(1) (3) (3) (2) (2)
● Chip evacuation amount
2.000
a e × a p × v f 1,000
(1) (2) (3)
Q =
0 0.1 0.04
0.2 0.4 0.6 0.8 1.0 Feed Rate (mm/t)
N53
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