Calculation formula of hole machining
.Cutting speed( vc )
Vc(m/min)
: Cutting speed
D1 (mm)
: Drill bit diameter
(3.14)
: Circumference ratio
n (min-1)
: Rotation speed of spindle
 
* Dividing by 1000 is to convert mm into m
(Example) rotation speed of spindle is 1350min-1 and drill bit diameter is2,
calculate cutting speed.
 
(Answer) integrate=3.14D1=12N=1350 in the formula;
 
 

Therefore, derive that cutting speed is 50.9m/min
   
.Feed of spindle( vf ):
 
vf=frn (mm/min) vf(mm/m)
: Feeding speed (Z-axis) of spindle
fr (mm/rev)
: Feed per revolutions
n (min-1)
: Rotation speed of spindle
 
 
(Example)Feed per revolution is 0.2mm/rev and rotation speed is 1350min-1,calculate feeding speed of spindle.
 
(Answer) integrate=3.14D1=12N=1350 in the formula;
 
vf=frn = 0.2 1350=270 mm/min
 
From here, it is derived that feeding distance of spindle is 270mm/min
   
.Hole machining time( Tc )
 
 
Tc(min)
: Machining time
n (min-1)
: Rotation speed of spindle
Id(mm)
: Depth of drilled holes
fr(mm/rev)
: Feed per revolution
I
: Number of hole
(Example) Drill bit a hole of15 and 30mm deep in SCM440 steel,
cutting speed is 50m/min, and feed per revolution is 0.15mm/rev.
Calculate cutting time.

 
 
(Answer) rotation speed of spindle
11.3 Seconds can finished.