Experimental investigation on fiber and CO2 inert gas fusion cutting of AZ31 magnesium alloy sheets

The influence of processing parameters and laser source type on cutting edge quality of AZ31 magnesium alloy sheets and differences in cutting efficiency between fiber and CO2 lasers were studied. A first part of the cutting experiments compared a fiber and CO2 laser source when cutting 1mm thick sheets in continuous wave mode and using Argon as an assist gas. The effects of cutting speed and assist gas pressure were investigated and optimal conditions were identified. In the second part of the experimental investigation, 3.3mm thick sheets were cut using fiber laser. Focal position and cutting speed were varied in order to detect the optimal combination of processing parameters to obtain the best edge quality. For both sheet thicknesses investigated, surface roughness, dross height, and striation pattern inclination were measured. Cutting quality assessment and classification was carried out according to UNI EN ISO 9013 standard. Results showed that productivity, process efficiency and cutting edges quality obtained using fiber lasers outperform CO2 laser performances and therefore are considered suitable for application like sheet metal trimming. ► Comparison on fiber and CO2 laser cutting performances. ► Better cutting quality of fiber laser 1mm thick sheets cuts with respect to the CO2 laser. ► Optimal fiber laser cutting condition for 3.3mm thick sheets with the most underfocused position and higher assist cut pressure. ► Better absorptivity of molten magnesium for unpolarized laser radiation for fiber laser cuts. ► Fiber lasers are suitable for application like sheet metal trimming on magnesium alloys.