3-D Transient Simulation Model for Laser Micromilling Processes

In this paper a laser milling simulator package is shown and discussed. The software system has been developed to simulate the micromanufacturing process using solid state lasers with pulse width in the range of 10-100 ns, but it can simulate every spatial and temporal distribution of the laser beam, so it is well suited to simulate both continuous and pulsed emission and every kind of laser spot distribution and trajectory. The system can simulate the effect of the laser beam on the workpiece, keeping into account the surface conditions, the evolution of the workpiece temperature field, the phase changes in the material and, at the end, the ablation rate. Particular attention has been focused in considering the influence of the plasma plume. Modeling and simulating the plasma plume creation and expansion is a very hard task, in the proposed package a simplified model is developed avoiding the fluid dynamic effects. In this work two empirical tuning parameters are considered: the first one is a global dispersion factor that keep in account the fraction of energy lost in the environment by the plume; the second one is a spreading factor that permits to model the irradiated energy of the laser beam hitting the workpiece and due to the plasma plume. The direct and coupled effects of these two parameters are evaluated and discussed