AE signals as laser cutting quality indicators

The paper presents results of an analysis of acoustic emission (AE) signals obtained during laser cutting of a steel plate, which is frequently used in the production of automotive body components. The acoustic emission in the plate, which is produced by various physical phenomena occurring during the laser cutting process, was measured with contact PZT sensors. During the laser cutting process, continuous AE signals, which are produced by the action of a cutting gas, were captured. After laser cutting, AE bursts produced by various phenomena during material cooling were captured. The results obtained confirm that both the continuous signals occurring during the cutting process and the AE bursts after laser cutting provide a good insight into the quality of a laser cut performed. Results of a factorial analysis of an influence of laser cutting conditions on the measured continuous AE signals are described. Response surfaces of amplitude average and intensity average and their mutual correlation are established. An influence of cutting parameters on the size of a dross formed at the lower laser-cut edge, which is an important indicator of cut quality, is analysed and a relation with the measured AE signals is established.