FORMULAE FOR FACE MILLING
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
(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)
(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?
(Answer)
Substitute the above figures into the formulae.
fz=vf÷(z×n)=500÷(10×500)=0.1mm/tooth
The answer is 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
(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?
(Answer)
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)
(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)
(Answer)
Calculate table feed per min vf=0.25×16×200=800mm/min
Calculate total table feed length. L=300+200=500mm
Substitute the above answers into the formulae.
Tc=500÷800=0.625(min)
0.625×60=37.5(sec). The answer is 37.5 sec.