Laser cutting melt film expulsion
The physical process of expelling liquefied metal from the kerf using a coaxial process gas. The flow dynamics prevent residue formation on the lower edge.
During laser cutting, the beam melts the material. You have to reliably push this melt film out of the kerf with the process gas (usually nitrogen or compressed air). If the film is not blown out cleanly, it remains as slag on the bottom edge. This is a real problem: these residues cause stresses in the material and can lead to cracks. Especially with thin or high-quality sheets, this is a rejection criterion. Adjust the gas pressure and the nozzle so that the cutting beam and the gas flow match. The gas jet must completely push away the melt film, otherwise the cut edge becomes unclean and the parts get hotter than necessary. You can recognize a clean cut by a smooth, burr-free bottom edge.