Visualization of events inside kerfs during laser cutting of fusible metal

The subject of the research is mechanism of melt removal and striated roughness generation. Being the main obstacle limiting laser cutting process performance, these phenomena are widely discussed. Available theoretical descriptions are not conclusive, as they have nothing to be verified with. High temperatures and narrowness of the kerf severely limit visual access at a real facility. Observation will become possible if one wall of the kerf is made of glass. This possibility is utilized in present experiments, which reproduce the process at low temperatures. Rose’s alloy (melting at 96 °C) is cut by reduced power laser beam (below 300 W) and high-speed photographic recordings are done. The experiments are carried out for thick materials (10 and 20 mm) under cut. Examination of the video data brought out innovative views on the melt removal. The cutting front was noted to be upright. The striation structure was observed to be generated at a certain distance from the cutting front and without direct assistance of laser radiation. Adequacy of the model experiment to the real case was confirmed by direct comparison of surfaces and by analysis of similarity relations.