Exercise 8 a) Estimate the time it takes to mill a 250 x 25 mm brass blank when using an HS 10 teeth cutting tool with diameter D = 150 mm in, the cutting speed V is 230 m/min, feed f = 0.2 mm / rev. The cutting speed is given by the relation V = D N, [m / min], where N is the speed [rev / min]. The speed of the workpiece is given by the relation v = f * N * n, [mm / min]. The time is given by the relation t = l + lc / V, [min.], where l is the length of the workpiece and lc corresponds to the radius of the cutting tool. b) A 300 mm long and 25 mm thick plate is divided into a band saw at a speed of 45 m/min., the saw blade has 480 teeth per meter. Estimate how long it will take to saw the plate longitudinally when the feed is 0.075 mm per tooth