Project ForgeIn orthogonal turning of a bar of 100 mm diameter with a feed of 0.25 mm/rev, depth of cut of 4 mm and cutting velocity of 90 m/min, it is observed that the main (tangential) cutting force is perpendicular to the friction force acting at the chip-tool interface. The main (tangential) cutting force is 1500 N. The orthogonal rake angle of the cutting tool in degree is
- zero
- B3.58
- C5
- D7.16
Explanation
In the Merchant circle force diagram, the friction-force axis (F) is inclined at angle (90°−α) from the cutting-force axis (Fc), where α is the rake angle — this follows purely from the geometry of the rake face relative to the cutting-velocity direction, independent of the friction angle β. If Fc is exactly perpendicular to F, then 90°−α=90°, which forces α=0.
Source: GATE ME 2013 (Booklet Code A) (2013)
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