9 OPERATING FORMULAS Milling Terminology/Operating Formulas The following terms and formulas can be used to determine the appropriate operating parameters. Formulas (Metric) Terms Formulas (Imperial) vc [m/min] Cutting speed SFM [ft/min] Vc = n × DC × p1000 n [rev/min] Spindle speed RPM [rev/min] SFM = RPM × DC × p12 n= vc × 1000DC × p Vf [mm/min] Feed rate IPM [in/min]fz[mm/z]Feed per toothIPT[in/T]RPM = SFM × 12 DC × p Vf = fz × z × n DC [mm] Cutting diameter DC [in] IPM = IPT × T × RPM fz = Vfz×n z [–]APMX FFW[mm] Number of teethDepth of cutT [–]DOC[in]IPT = IPMT × RPM Q= Vf × APMX FFW × APMX EFW1000APMX EFW [mm] Width of cut WOC [in] MRR = IPM × DOC × WOC Q [cm³/min] Metal removal rate MRR in³/min 210