Direction: In an orthogonal machining operation:
Uncut thickness = 0.5 mm
Cutting speed = 20 m/min
Rake angle = 15°
Width of cut = 5 mm
Chip thickness = 0.7 mm
Thrust force = 200 N
Cutting force = 1200 N
Assume Merchants theory.
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The percentage of total energy dissipated due to friction at the tool-chip interface is
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- 30%
- 42%
- 58%
- 70%
Correct Option: A
Total heat generated, Q1 = Fc × V = 24000 J/min
Heat dissipated due to friction, Q2 = F × r × v
Frictional force, F = Fc sin α + Ff cos α = 503.76 N
Q2 =7193.69 J/min.
| ∴ | = 0.299; 30% | |
| Q2 |
