Calculation formula of hole machining
Ąô.Cutting speed( vc )
 Vc(m/min) : Cutting speed D1 (mm) : Drill bit diameter ĶÐ (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 isĶÕ2, calculate cutting speed. (Answer) integrateĶÐ=3.14ĢŽD1=12ĢŽN=1350 in the formula; Therefore, derive that cutting speed is 50.9m/min
Ąô.Feed of spindle( vf ):

 vf=frĄĪn (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) integrateĶÐ=3.14ĢŽD1=12ĢŽN=1350 in the formula; vf=frĄÁn = 0.2 ĄÁ1350=270 mm/min From here, it is derived that feeding distance of spindle is 270mm/min
Ąô.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 ofĶÕ15 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. -102-