Ti Surface Laser Polishing: Effect of Laser Path and Assist Gas

Laser polishing is a process by which the surface roughness of machined parts can be reduced avoiding ablation phenomena. In this process the laser spot irradiates the sample surface with short laser pulses at a power density that causes a surface melting of the order of few nanometers. Compared to conventional polishing process (as grinding) it ensures the possibility of avoiding any surface orientation, no tool wear, no abrasive or liquids, no debris and less machining time; moreover coupled with a galvo system it results to be more suitable in case of 3D complex workpieces. Nowadays, on this process, several authors are focusing their attention on the wavelength and pulse length effect but a lack of knowledge concerning the effect of other process parameters still exists. In this work the effects of laser path and assist gas were tested by the authors. Nd:YVO4 laser source, characterized by a wavelength equal to 532 nm, was used in the experiments and Ti grade 2 samples were selected. A full experimental plan was designed to investigate the influence of process parameters in terms of average roughness reduction achieved.