A modeling study on the influence of pulse shaping on keyhole laser welding

A theoretical analysis describing the effects of pulse shaping on keyhole laser welding is presented. Calculation of the keyhole profile and melt pool dimensions was performed by the balancing of surface forces and energy at the liquid-vapor and solid-liquid interfaces in three dimensions. The effect of temporal pulse shape on weld dimensions has been examined over a range of power densities, pulse times and pulse frequencies. Several pulse types (e.g., top-hat, Gaussian, ramp-up and ramp-down pulses) have been considered. Pulse shaping showed significant effect on the weld dimensions. The predicted width and penetration depth of welds with ramp-up and ramp-down pulse shapes were greater than those obtained with Gaussian and top-hat pulses. The theoretical predictions have been compared with experimental data. Furthermore, the response of two different materials with considerably different physical properties (stainless steel and aluminum) has been analysed.