CO₂ laser-air cutting of glass-fibre-reinforced unsaturated polyester (GFRUP): an experimental investigation

Glass-fibre-reinforced unsaturated polyester (GFRUP) is one the thermoset composites that has many applications in manufacturing engineering. CO₂ laser cutting of this composite has been significantly developed in industries. It is believed that the presence of glass fibre network in the matrix of thermoset affects the laser cutting process of this composite. In addition, the three-dimensional matrix of monomers along with carbon atoms in the atomic network’s joints can also influence the laser cutting parameters. The aim of this research is to experimentally investigate the effect of these complicated structural properties on the CO₂ laser-air cutting of GFRUP sheets. First, the maximum cutting speeds, in which the cut occurs, were obtained for various sheet thicknesses using a variety of powers. The kerf width was measured with using an optical stereo-microscope. Then, the laser cutting mechanism was discussed using the SEM of the cut edge surfaces. The volume cutting efficiency was also studied. The results indicate that the upper kerf width is wider than the lower kerf width. The upper kerf width is larger than the spot size of 0.3 mm. The chaotic striations on the cut edge surface are the resolidified carbon-glass fibres compounds and can be seen as something like stalactites which are in black due to the carbon dust. Opening of the lower kerf due to the shrinkage of the resolidified carbon-glass fibre compounds is reported as a phenomenon. The cutting efficiency decreases as the sheet thickness increases.