Direction: Orthogonal turning is performed on a cylindrical workpiece with shear strength of 250 MPa. The following conditions are used: cutting velocity is 180 m/min, feed is 0.20 mm/rev, depth of cut is 3 mm, chip thickness ratio = 0.5. The orthogonal rake angle is 7°. Apply Merchants theory for analysis.
-
The shear plane angle (in degrees) and the shear force respectively are
-
- 52; 320 N
- 52; 400 N
- 28; 400 N
- 28; 320 N
Correct Option: D
| tanφ= | = | = 0.503 | ||
| 1 − rsinα | 1 − 0.5sin7° |
φ = 28°
Now, shear force = shear stress × area
F = 250 × AB width of cut
| ∴ AB = | = | = 0.43 | ||
| sin28° | sin28° |
where AC is incut chip thickness
Now width ≌ depth of cut = 3 mm
F = 250 × 0.43 ×3
≌ 320 N
