9 FORMULAS Value Unit Formula vc . 1000 Number of revolutions [rev/min] n= DC . p p . DC . n Cutting speed [m/min] vc = 1000 Feed per revolution [mm/rev] frev = fminn = fz . z Feed per minute (speed of feed) [mm/min] fmin = vf = frev . n = fz . z .n Feed per tooth [mm/tooth] fz = frevz= fminn.z Chip cross section [mm2] A = fz . ap Chip thickness (for inserts with a straight edge) [mm] h = fz . sin kr Chip thickness (for round cutting inserts) [mm] h= fz . ap INSD Metal removal rate [cm3/min] Q= ap . ae . fmin1000 ap . ae . fmin Power demand [kW] Pc = 60 . 10 6 . h . kc . kg Approximate power demand [kW] Pc = ap . ae . fminx Note: Quantity Unit Quantity Unit n Number of revolutions [rev/min] h Chip thickness [mm] DC Diameter (of tool or work piece) [mm] Q Material removal rate per minute [cm3/min] vc Cutting speed [m/min] Pc Power demand [kW] frev Feed per revolution [mm/rev] kc Cutting force per mm2 [MPa] A Chip cross section [mm2] kg Coefficient of influence of angle g0 [°] ap Axial depth of cut (depth of cut) [mm] h Machine efficiency usually h = 0,75 [-] ae Radial depth of cut (width of cut) [mm] x Coefficient of influence of work piece material [-] kr Setting angle [°] fmin Feed per minute (sometimes called speed of feed) [mm/min] Material Steel Cast iron Al fz Feed per tooth [mm/tooth] z Number of teeth [-] Coefficient x 24 000 30 000 120 000 INSD Diameter of insert [mm] 783