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# FORMULAS FOR MILLING

Inch
CUTTING SPEED (vc) vc (SFM)
:Cutting Speed
D1 (inch)
:Cutter Diameter
π (3.14)
:Pi
n (min-1)
:Main Axis Spindle Speed
Check the item you want to calculate, input values in the two boxes, and then press the Calculate button.
D (inch)
n (min-1)
vc (Problem) :
What is the cutting speed when main axis spindle speed is 350min-1 and cutter diameter is Ø5" ?

Substitute π3.14, D=5", n=350 into the formulae.
vc =π×D×n÷12=3.14×5"×350÷12= 457.9SFM
The cutting speed is 457.9SFM.

FEED PER TOOTH (fz) fz (IPT)
:Feed per Tooth
z
:Insert Number
vf(inch/min)
:Table Feed per Min.
n (min-1)
:Main Axis Spindle Speed (Feed per Revolution fr=z x fz)
Check the item you want to calculate, input values in the three boxes, and then press the Calculate button.
vf (inch/min)
z
n (min-1)
fz (Problem) :
What is the feed per tooth when the main axis spindle speed is 500min-1, insert number is 10, and table feed is 20inch/min ?

Substitute the above figures into the formulae.
fz =Vf÷(z×n)=20÷(10×500) = .004IPT

TABLE FEED (vf) vf(inch/min)
:Table Feed per Min.
fz (IPT)
:Feed per Tooth
n (min-1)
:Main Axis Spindle Speed
z
:Insert Number
Input the values
fz
z
n(min-1)

vf (Problem) :
What is the table feed when feed per tooth is .004IPT, insert number is 10, and main axis spindle speed is 500min-1?

Substitute the above figures into the formulae.
vf = fz×z×n = .004IPT×10×500 = 20inch/min
The table feed is 20inch/min.

CUTTING TIME (Tc) Tc (min)
:Cutting Time
vf(inch/min)
:Table Feed per Min.
L (inch)
:Total Table Feed Length (Workpiece Length(l)+Cutter Diameter(D1)
Input the values
L (inch)
vf (inch/min)

Tc (min)
second (s) (Problem) :
What is the cutting time required for finishing 4" width and 12" length surface of a cast iron (GG20) block when cutter diameter is Ø4", the number of inserts is 16, the cutting speed is 410SFM , and feed per tooth is .01. (spindle speed is 200min-1)

Calculate table feed per min vf=.01×16×200=32inch/min
Calculate total table feed length. L=12+4=16inch
Substitute the above answers into the formulae.
Tc =16÷32= 0.5(min) TOP

Metric
CUTTING SPEED (vc) * Divide by 1,000 to change to m from mm.
vc (m/min)
Cutting Speed
D1 (mm)
Cutter Diameter
π (3.14)
Pi
n(min-1)
Main Axis Spindle Speed

Check the item you want to calculate, input values in the two boxes, and then press the Calculate button.
D1 (mm)
n (min-1)
vc (m/min) (Problem)
What is the cutting speed when main axis spindle speed is 350min-1 and cutter diameter isø125? (Answer)
Substitute π=3.14, D1=125, n=350 into the formulae.
vc=(π×D1×n)÷1000=(3.14×125×350)÷1000 =137.4(m/min)
The cutting speed is 137.4 m/min.

FEED PER TOOTH (fz) fz (mm/tooth)
Feed perTtooth
z
Insert Number
vf (mm/min)
Table Feed per Min.
n (min-1)
Main Axis Spindle Speed (Feed per Revolution f = z x fz)
Check the item you want to calculate, input values in the three boxes, and then press the Calculate button.
vf (mm/min)
z
n (min-1)
fz (mm/tooth) (Problem)
What is the feed per tooth when the main axis spindle speed is 500min-1, insert number is 10, and table feed is 500mm/min?
Substitute the above figures into the formulae.
fz=vf÷(z×n)=500÷(10×500)=0.1mm/tooth

TABLE FEED (vf) vf (mm/min)
Table Feed per Min.
z
Insert Number
fz (mm/tooth)
Feed per Tooth
n (min-1)
Main Axis Spindle Speed
Input the values
fz
z
n(min-1)

vf (Problem)
What is the table feed when feed per tooth is 0.1mm/tooth, insert number is 10, and main axis spindle speed is 500min-1?
Substitute the above figures into the formulae.
vf=fz×z×n=0.1×10×500=500mm/min
The table feed is 500 mm/min.

CUTTING TIME (Tc) Tc(min)
Cutting Time
vf(mm/min)
Table Feed per Min.
L (mm)
Total Table Feed Length (Workpiece Length: l+Cutter Diameter: D1)
Input the values
L (mm)
vf (mm/min)

Tc (min)
second (s) (Problem)
What is the cutting time required for finishing 100 mm width and 300 length surface of a cast iron (GG20) block when cutter diameter is ø200, the number of inserts is 16, the cutting speed is 125m/min, and feed per tooth is 0.25 mm. (spindle speed is 200 min-1) TOP BACK