
153Cutting Cylindrical Surfaces
Problems
Turning
5.1 It is required to face a disk of 450 mm outer diameter with a central
hole of 150 mm. A lathe machine is used for that job, the spindle speed
is 50 rpm, feed rate is 0.3 mm/rev, and the depth of cut is 2.5 mm.
The specic cutting energy at these cutting conditions is 1550 N/mm
2
.
Calculate
a. The machining time
b. The power consumption at the beginning of the operation
c. The power consumption at the end of the operation
5.2 If the disk in the preceding problem is faced at a constant surface speed
of 60 m/min, calculate
a. The rotational speed at the start
b. The rotational speed at the ...