Q5.12 A 100mm diameter bar is turned in one pass on a lathe to 90mm. The specific cutting energy is 2.48 GJ/m³. A tool life of 8 hours is desired. The appropriate tool life equations for these conditions are: V-T"-60 3.1018 T= 10.8.16 where T(min), v(m/min). f(mm/rev), d(mm) Calculate: a) the tool life exponent, n, (ANS: n=0.1) b) the cutting speed, V, (ANS: 32.4 m/min) c) feed rate, f. (ANS: 0.365 mm/rev) d) main cutting force, F., (ANS: 4.5 kN) e) and required power at the tool tip. (ANS: 2.4 kW)