Flowchart for Selecting Optimum Spindle SizeVariables Defined

D [mm]Diameter of tool or workpieced [mm]Depth of cut E*Efficiency of spindle drivef
t [mm]Feed rate per toothf
m [mm/min]Feed rateK [cm
3 /kW min]Unit power constantn [rpm]Spindle speed P
s [kW]Power at spindleP
m [kW]Power at motorQ [cm
3 /min]Metal removal rateV
c [m/min]Cutting speedw [mm]Width of cutzNumber of teeth in cutter* for direct belt-drive use 90% (0.90) Converting kW to torque (Nm):T = kW x 9550rpm

Standard values for K

Cast irons15...30Steel - plain carbon15...30 Steel - alloys10...15 Steel - tool5...10 Steel - stainless5...10 Aluminum alloys60...70 Cooper alloys15...25 Nickel alloys5...10 Titanium10...15
Note: Refer to Spindle Selection Chart on page 6 for optimum spindle size selection. 31