GATE 2020 ME (ME1) – Question 55
In orthogonal turning, a 100 mm long chip is obtained from an uncut chip length of 250 mm. Cutting speed is 30 m/min and rake angle 20°. Find shear-plane angle (degrees), to one decimal.
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Correct answer: 22 to 25
Explanation
Volume conservation gives chip ratio r=chip length/uncut length=100/250=0.4. Merchant geometry gives $\tan\phi=r\cos\alpha/(1-r\sin\alpha)=0.43545$. Hence φ≈**23.5°**. The given cutting speed is not needed for this geometrical calculation.