## Formula for Drilling

Cutting speed (vc)

*Divide by 1,000 to change to m from mm.
vc (m/min) : Cutting Speed
DC (mm) : Drill 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.
n(min-1)
DC(mm)
vc(m/min)

（Problem）
What is the cutting speed when main axis spindle speed is 1350min-1 and drill diameter is 12mm ?
Substitute π=3.14, DC=12, n=1350 into the formula
vc=π×DC×n÷1000=3.14×12×1350=50.9m/min
The cutting speed is 50.9m/min.

Feed of the main spindle (vf)
vf(mm/min)：Feed Speed of the Main Spindle (Z axis)
fr(mm/rev)：Feed per Revolution
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.
fr(mm/rev)
n(min-1)
vf(mm/min)

（Problem）
What is the spindle feed (vf) when the feed per revolution is 0.2mm/rev and main axis spindle speed is 1350min-1 ? （Answer）
Substitute fr=0.2,n=1350 into the formula
vf=fr×n=0.2×1350=270mm/min
The spindle feed is 270mm/min.

Drilling time (Tc)
Tc (min) : Drilling Time
n (min-1) : Spindle Speed
ld (mm) : Hole Depth
fr (mm/rev): Feed per Revolution
i : Number of Holes
Input the values
ld(mm)
i
n(min-1)
fr(mm/rev)

Tc(min)
sec.

（Problem）
What is the drilling time required for drilling a 30mm length hole in alloy steel (JIS SCM440) at a cutting speed of 50m/min and a feed 0.15mm/rev ?

n=（50×1000）÷(15×3.14)=1061.57min-1
Tc=(30×1)÷(1061.57×0.15)=0.188
=0.188×60≒11.3sec