THERMAL MODELLING OF LASER ABLATION SIMULATION BY NUMERICAL SOLUTION OF A THREE PHASE STEPHAN PROBLEM

Laser ablation is an important industrial process to remove material from a solid surface by means of a laser beam that heats and evaporates or sublimates the material. One of the most interesting applications of such technique is the laser machining, technique that allow to drill holes and perform other operations on even very hard material in an extremely precise way. Usually this process is performed not continuously but with a pulsed laser, meaning that an extremely high amount of energy is discharged on an extremely small surface, achieving a strong energy density in a small amount of time such that the surrounding material absorbs a very small amount of energy; consequently it does not heat, preserving its properties. This process can be easily modeled as a three phase Stephan problem to which a finite difference solution with the Front Tracking Method is applied. Such methodology has been already used by authors to model electrodes erosion by the establishing of electric arches, with good agreement with literature data. The same methodology is now applied to laser ablation technique taking into account the additional energy contribution mechanisms that could have been previously negligible for an electric arc shock but that are of high relevance in a laser ablation process.