Direction: A low carbon steel bar of 147 mm diameter with a length of 630 mm is being turned with uncoated carbide insert. The observed tool lives are 24 min and 12 min for cutting velocities of 90 m/min and 120 m/min respectively. The feed and depth of cut are 0.2 mm/ rev and 2 mm respectively. Use the unmachined diameter to calculate the cutting velocity.
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Neglect over-travel or approach of the tool. When tool life is 20 min, the machining time in min for a single pass is
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- 5
- 10
- 15
- 20
Correct Option: C
V = πDN
N =210.2 rpm
∴ Machining time,
| tm= | = .15min. | |
| N |
