Investigation on disk and CO2 laser beam fusion cutting differences based on power balance equation

In this work the calculation of the process temperatures in fusion cutting was carried out based on the power balance approach. Cutting experiments with CO2 and disk lasers were performed on 1, 5 and 8 mm thick cold work tool steel sheets. The experimental, numerical and analytical evaluation of the single terms of the power balance equation allowed the explanation of the observed cut quality differences between disk and CO2 laser cuts. Lower process temperatures calculated by a power balance equation for disk laser cuts lead to the increase of viscosity of molten material. The subsequent increase in difficulty for ejection of the molten material from the cut kerf explains the worse cut quality if compared with CO2 laser cuts. Experimental evidence and theoretical calculations showed that the additional physical mechanisms like plasma formation should be considered in the overall power balance under particular cutting conditions.

► Comparative investigation of disk and CO2 laser fusion cutting performances.
► Evaluation of the single terms of the power balance equation allows the explanation of differences.
► Lower process temperatures calculated for disk laser cuts.
► Higher viscosity of molten material results in difficult ejection from the cut kerf.
► Additional mechanisms like plasma formation to be considered in the power balance.