In the draw follow u ing operation the data are given cuttin

In the draw follow u ing operation, the data are given cutting energy 2.3 J /mm S pe c Rotational frequency noo R pm Feed per revolution .3 mm Drill iameter and point ang 11 mm calculate ol Un -deb meel cross sectional area ip in mm 2 The tourque in m arly ng on the drill daring is ore spine

Solution

Assuming drill to be of double flute so z = 2

here n = 400 rpm

feed(f)= 0.3 mm per rev

pie = 118 degree

dia of drill (d)= 14mm

Therefore, feed rate (v) = f.n = 400*0.3 = 120 mm per minute

depth of cut, dw = d/2 = 14/2 = 7mm

material removal rate = 250f.v.d = 250*0.3*14 = 1050 mm cube per minute

undeformed thickness (hD) = (f/z)sin(pie/2) = 0.095 mm

undeformed width (bD) = (d/2) / sin(pie/2) = 10.99 mm

hence undeformed cross section area = hD*bD = 1.044