A laser beam with a power intensity of 105 Wmm2 is used to m

A laser beam with a power intensity of 10^5 W/mm^2 is used to machine 3 mm thick nickel sheet with a 100 um waist diameter with a 5 us pulse in a 20 us cycle. Melting temperature = 1720 K and boiling temperature of Temperature of Nickel =3150 K. density, (rho)= 8900 kg/m^3, thermal conductivity, k= 90 W/cm°C. Specific heat in liquid and solid state, c =0.444 J/kg/K . Latent heat of evaporation = 7x10^6 J/kg. Latent heat of melting is 1% of the latent heat of evaporation. Assume 10% of the laser power is used.

A) Estimate the time required for the material at center of the beam to reach it melting temperature.

B) Assuming the metal removed as a spherical cap of the diameter equal to the beam waist diameter, estimate the depth h of the cap in one pulse.

C) Estimate the metal removal rate in mm^3/s

D) Estimate the time required to drill though the hole

SO 286-1:2010(E) Values of the fundamental deviations for shafts a to j Table 4 Fundamental deviation values in micrometres Fundamental deviation values Nominal size Uppe mit deviation. Lower deviation Up to All standard tolerance grades and Above nclud ng 3 270 -140 -50 .34 20 -14 -10 4 -21 0 4-6 3 6 270 -140 46 30 20 -14 -10 -4 0 10 230 -150 -30 -56 -40 -25 -18 -13 -3 -5 180 -340 -240 200 225 -40 260 170 15 13 21 225 250 -420 280 900

Solution

The answer of the following question is as follows .

The required time for the material to reach the centre is 1.2 min .

The depth is 75mm