Excimer Laser Cutting: Experimental Characterization and 3D Numerical Modelling for Polyester Resins

Excimer laser has been proposed in these years as a new technology for precision cutting of plastic materials, due to the photo ablative mechanism and to the low thermal damage. Previous experiments, done by the authors, on the cutting of kevlar reinforced composites with epoxy matrix, using excimer laser, highlighted very high qualities not attainable with other technologies. In the present work the attention was focused on thermoset polyester resin, because of the extensive use of this material as matrix for plastic composites. The methodology proposed in this work allows to simulate in three dimensions the laser cutting shape and size by means of a photo-ablation approach, that takes also into account the thermal effects. An experimental characterisation of the resin was performed to determine the threshold fluence (energy surface density) and the other material parameters needed to apply a photo-ablation model. The numerical simulations, compared with the experimental cuts, gave results in good accordance in terms of shape and depth of cut.