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 examined by the comparison of numerical simulation results with those obtained by analytical models. Results showed that good agreement on the conduction loss power was obtained for all the test cases considered in this study. The conduction losses estimation allows justifying the lower quality of disk laser cuts related to the lower average cut front temperature resulting in the increase of viscosity of molten material and the subsequent more difficult ejection of the melted material from the cut kerf.