StreakPeaked· Practice

ExamsGATETechnical

The length, width and thickness of a steel sample are 400 mm, 40 mm and 20 mm, respectively. Its thickness needs to be uniformly reduced by 2 mm in a single pass by using horizontal slab milling. The milling cutter (diameter: 100 mm, width: 50 mm) has 20 teeth and rotates at 1200 rpm. The feed per tooth is 0.05 mm. The feed direction is along the length of the sample. If the over-travel distance is the same as the approach distance, the approach distance and time taken to complete the required machining task are

  1. 14 mm, 18.4 s
  2. 21 mm, 28.9 s
  3. 21 mm, 39.4 s
  4. 14 mm, 21.4 s

Correct answer: 14 mm, 21.4 s

Solution

Approach (and over-travel) distance = sqrt(d(D-d)) = sqrt(2*98) = 14 mm. Feed rate = 0.05*20*1200 = 1200 mm/min = 20 mm/s, total travel = 400+14+14 = 428 mm, time = 428/20 = 21.4 s. Answer is 14 mm, 21.4 s.

Related GATE Technical questions

⚔️ Practice GATE Technical free + battle 1v1 →