Solve the following and send me your detailed answer. The end of a large tubular work part is faced on a vertical boring mill. The outside diameter = 900 mm, inside diameter = 500 mm, and height = 450 mm. If the facing operation is performed at a rotational speed = 40 rev/min, feed = 0.4 mm/rev, and depth of cut = 4.5 mm, determine the (a) cutting time to complete the facing operation and (b) cutting speeds and metal removal rates at the beginning and end of the cut.