Modelling the laser fusion cutting process: III. Effects of various process parameters on cut kerf quality

Based on the models for determining the geometry of the cutting front and the gas flow distribution inside the cut kerf of the laser fusion cutting process, the effects of the inlet stagnation pressure of the nozzle, the exit diameter of the supersonic nozzle, laser power, cutting speed and focal position upon the geometry of the cutting front and the flow field distribution which subsequently affect the cut edge quality are analysed in this paper. The theoretical predictions are verified by practical laser fusion cutting experiments using a high-power CO2 laser, a supersonic nozzle and a high-pressure cut-assisted gas in the range of 5 bar and above. The theoretical predictions are used to explain the roughness, the ripple directions and the amount of dross on the experimental cut edges.