MITSUBISHI MATERIALS CORPORATION
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FORMULAS FOR DRILLING

Inch
CUTTING SPEED (vc)
Formula
vc (SFM)
:Cutting Speed
D1 (inch)
:Drill Diameter
π(3.14)
:Circular Constant
n (min-1)
:Rotational Speed of the Main Spindle
Check the item you want to calculate, input values in the two boxes, and then press the Calculate button.
n (min-1)
D1 (inch)
vc (SFM)


image
*Unit transformation (from "mm" to "m")
(Problem) :
What is the cutting speed when main axis spindle speed is 1350min-1 and drill diameter is .500inch ?

(Answer):
Substitute π=3.14, D1=.500inch, n=1350 into the formulae
vc=π× D1×n÷12=3.14×.500×1350÷12=176.6SFM

The cutting speed is176.6SFM.



FEED OF THE MAIN SPINDLE (vf)
Formula
vf (inch/min)
:Feed Speed of the Main Spindle (Z axis)
fr (IPR)
:Feed per Revolution
n (min-1)
:Rotational Speed of the Main Spindle
Input the values
fr
n (min-1)

Vf (inch/min)

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(Problem):
What is the spindle feed (vf) when feed per revolution is .008IPR and main axis spindle speed is 1350min-1?

(Answer):
Substitute fr=.008, n=1350 into the formulae
vf = fr×n = .008×1350 = 10.8inch/min
The spindle feed is 10.8inch/min.


DRILLING TIME (Tc)
Formula
Tc (min)
:Drilling Time
n (min-1)
:Spindle Speed
ld (inch)
:Hole Depth
fr (IPR)
:Feed per Revolution
i
:Number of Holes
Input the values
n (min-1)
Id
i(inch)
fr (IPR)

Tc(min)
second (s)

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(Problem):
What is the drilling time required for drilling a 1.2inch length hole in alloy steel at a cutting speed of 165SFM and feed .006IPR ?

(Answer):
Spindle Speed n =(165×12)÷ (.59×3.14) = 1068.8min-1

Tc =(1.2×1)÷ (1068.8×.006) = .187
= .187×60≒11.2 sec

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Metric
CUTTING SPEED (vc)
Calculate
*Unit transformation (from "mm" to "m")
vc (m/min)
Cutting Speed
D1 (mm)
Drill Diameter
π (3.14)
Pi
n (min-1)
Rotational Speed of the Main Spindle
Input the values
n (min-1)
D1(mm)
vc (m/min)


Graphic Image
(Problem)
What is the cutting speed when main axis spindle speed is 1350min-1 and drill diameter is 12mm ?
(Answer)
Substitute π =3.14, D1=12,n=1350 into the formulae
vc =(π ×D1×n)÷1000 =(3.14×12×1350)÷1000=50.9m/min
The cutting speed is 50.9m/min.

FEED OF THE MAIN SPINDLE (vf)
Calculate
vf(mm/min)
Feed Speed of the Main Spindle(Z axis)
f (mm/rev)
Feed per Revolution
n (min-1)
Rotational Speed of the Main Spindle
Input the values
f (mm/rev)
n(min-1)
vf (mm/min)


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

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

Tc (min)
second (s)

Graphic Image
(Problem)
What is the drilling time required for drilling a 30mm length hole in alloy steel at a cutting speed of 50m/min and feed 0.15mm/rev ?
(Answer)
Spindle Speed
n=(50×1000)÷(15×3.14)=1061.57min-1
Tc=(30×1)÷(1061.57×0.15)=0.188
=0.188×60=11.3sec.