Estimation of Machining Time in Boring
In boring operation the machining time is calculated the same manner as in turning. It is given by the following relation:
Equation 1
Machining Time = Depth of hole to be bored in mm minutes/ N × feed or rev
Where, N = No. of revolutions per min. of machine spindle or work.
Example
In cast iron housing a hole of 30 mm diameter is to be bored to a depth of 50 mm. Calculate the machining time required for boring this hole assuming a cutting speed of 30 mpm and a feed of 0.2 mm per revolution.
Solution
N = Vc × 1000/ π× D
= 30 × 1000/ π× 30
= 318 rpm
Machining time =50 / (318 × 2)
= (50 × 60 )/ (318 × 0.2) = 47 secs.