Question

In turning a solid round bar, if the travel of the cutting tool in the direction of feed motion is 1000 mm, rotational speed of the workpiece is 500 rpm, and rate of feed is 0.2 mm/revolution, then the machining time will be 
1. 10 seconds
2. 100 seconds
3. 5 minutes
4. 10 minutes

Answer 1

Correct Answer - Option 4 : 10 minutes

Concept:

Machining time (Tm) is given by,

\({T_m} = \frac{L}{{f \times N}}\)

D = diameter, N = speed in rpm, L = total length travelled by the tool, f = feed

\(cutting\;speed = \frac{{\pi \times D \times N}}{{1000}}\)

Calculation:

Given: L = 1000 mm; N = 500 rpm; f = 0.2 mm/revolution

Machining time will be 

\({T_m} = \frac{1000}{{0.2 \times 500}}\)

⇒ T_m = 10 minutes