Estimating cutting front temperature difference in disk and CO2 laser beam fusion cutting

A three-dimensional, semi-stationary, simplified thermal numerical model was developed. The average cutting front temperature difference in disk and CO2 laser beam fusion cutting of 90MnCrV8 was estimated by computing the conductive power loss. Basing on heat affected zone extension experimentally measured and using an inverse methodology approach, the unknown thermal load on the cutting front during laser cutting was calculated. The accuracy of the numerical power loss estimation was evaluated comparing the results from simulation with the ones from analytical models. A good agreement was found for all the test cases considered in this study. The conduction losses estimation was used for justifying the lower quality of disk laser cuts due to the lower average cut front temperature. This results in the increase of viscosity of molten material and in the subsequent more difficult ejection of the melted material from the cut kerf.

► Inverse methodology allows the accurate estimation of heat conduction losses in laser cutting.
► Analytical models confirms the accuracy of the numerical model.
► Higher values of conductive surface energy losses for CO2 laser cuts.
► CO2 laser average cut front temperature is higher than the case of disk laser.
► Hardness tests validate visual examination as accurate, fast method to measure HAZ.