Q 68. A 600 mm 300 mm flat surface of a plate is to be finish machined on a shaper. The plate has been fixed with the 600 mm side along the tool travel direction. If the tool over-travel at each end of the plate is 20 mm, average cutting speed is 8 m/min, feed rate is 0.3 mm/stroke and the ratio of return time to cutting time of the tool is 1 : 2, the time required for machining will be
(A) 8 minutes
(B) 12 minutes
(C) 16 minutes
(D) 20 minutes
Answer: (B)
Explanation:
