Numerical approach to pulsed laser heating of semi-infinite aluminum substance

Processing of the reflective materials, such as aluminum, with a pulsed CO₂ laser beam depends largely on laser output power and pulse form. To enhance the understanding of the effect of pulse parameters on laser machining a modeling of laser induced heating is essential. The present study develops the heat transfer model allowing temporal variation of CO₂ laser output pulse, phase change process and temperature dependent thermal properties. A numerical technique is introduced to solve the resulting heat transfer equation. Aluminum is selected as workpiece and its surface reflectivity is taken into account in the computation. Thermal integration due to repetitive pulsing is also discussed. It is found that time corresponding to maximum temperature can be predicted by proper selection of pulsed parameters and the ability of the material to follow the laser pulse profile depends upon the pulse shape.