Quality assessment of a laser cut based on captured acoustic emission signals

The paper presents results of an analysis of acoustic emission (AE) measurement in laser cutting of a DC04 steel plate. Laser cutting was evaluated on the basis of monitoring the acoustic emission in the course of cutting and of an analysis of events occurring in the material after the completion of laser cutting. It was found that the cutting oxygen flow was the primary source of AE in laser cutting. The incidence of the supersonic gas flow in the cutting front is reflected at an acoustic sensor in the form of continuous AE signals. The AE measured immediately after laser cutting is a result of various events in the heat-affected zone surrounding the laser cut and of the dross formed at the lower edge of the cut. It was proved that laser-cutting conditions set exerted a significant influence on the amplitude value and signal intensity of AE during and after cutting. It was confirmed separately that there is also a relation between a measured AE signal and dross formation at the lower edge of the cut..