GATE 2020 ME (ME1) – Question 52
A 25 mm × 25 mm slot is milled in a 300 mm long workpiece using a side-and-face cutter of diameter 100 mm, width 25 mm and 20 teeth. Depth of cut is 5 mm, feed per tooth 0.1 mm, cutting speed 35 m/min, and approach and overtravel are 5 mm each. Find milling time (min), to one decimal.
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Correct answer: 7 to 9
Explanation
Five passes are required. Spindle speed is $N=35000/(\pi100)=111.408$ rpm and feed is fz·z·N=222.817 mm/min. Travel per pass is 300+5+5=310 mm. Total time is 5×310/222.817=6.9564 min, or **7.0 min**.