Cutting condition Formula for Turning

※ Cutting Speed (vc)

vc=(π•Dm•n)/100

*Divide by 1000 to change to m from mm.
Vc (m/min) ： Cutting speed
Dm (mm)：Workpiece Diameter
π (3.14)： Pi
n (min-1)：Main Axis Spindle Speed

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※Cutting Power (Pc)


Pc= Ks×Vcxap×Xf / 6120×η

PHP= Ks×Vcxap×f / 4500×η

Pc(kW)：Cutting power
PHP(HP)：Cutting power
Vc(m/min)：Cutting speed
ap：Cutting depth
f(mm/rev)：Feed rate per minute of table
Ks (kgf/mm2)：Relative cutting resistance
η(0.7~0.8)：Mechanical efficienc

 

Approximate rate (Ks)
Mild Steels 190
Medium Steels 210
Hard Steels 240
Light Alloy 190
High Alloy 245
Cast Iron 93
Forging cast iron 120
Bronze / Brass 70

 

※ Theoretical finished surface roughness(Rz)

Rz(h)=(f2/8×R(rε))×1000

Rz(h)：Theoretical finished surface roughness
f(mm/rev)：Feed rate per minute of table
R(rε)：Nose Radius
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※Chip removal Volume (Q)

Q=Vc×ap×f
Q(cm3/min): Chip removal Volume
Vc(m/min):Cutting speed
ap(mm):Cutting depth
f(mm/rev)：Feed rate per minute of table

※Cutting Time (sec)

Tc = Im/I (min)
Tc(min) : Cutting Time
Im(inch) : Workpiece Length
I(inch/min) : Cutting Length per Min