Calculate the Machining Time and the Material Removal Rate
A through hole of 40 mm diameter and 50 mm depth is to be drilled in a mild steel component. The cutting speed can be taken as 65 m/min and the feed rate as 0.25 mm/rev. calculate the machining time and the material removal rate.
Solution
Given V = 65 m/min
f = 0.25 mm/rev
D = 40 mm
L = 50 mm
Spindle speed
N = (1000 × 65)/ (π× 40)
= 527.35 rev/min
= 520 rev/min
Breakthrough distance
A =40 /2 tan 59^{o}
Total length of drill travel L = 50 + 12 + 3 = 65 mm
Time for drilling the hole = 65/ (0.25 × 520) = 0.50 minutes
The material removal rate = (π× 40^{2} × 0.25 × 520) /4
= 163362.82 mm^{3}/min
= 163.363 cm^{3}/min.