TURBULENT BOUNDARY-LAYER APPROACH ALLOWING CHEMICAL-REACTIONS FOR CO2-LASER OXYGEN-ASSISTED CUTTING PROCESS

The present study presents a theoretical model for the laser gas-assis ted cutting mechanism which includes the chemical reactions, momentum and assisting gas effects as well as that of conduction and convection . A heat-transfer model based on a boundary layer consideration has be en adopted. In the analysis the relationship between the various param eters including power intensity, material thickness, gas jet velocity and cutting speed are predicted. A quantitative measure of chemical re actions between the molten and the assisting gas, evaporation of metal and the cooling effect of the gas jet are taken into account. The tur bulent boundary layer over the molten metal is considered. An experime nt is carried out to measure the cutting speed with different settings of laser power intensity. This provides a comparison between the theo retical predictions and experimental results. The experiment is extend ed to include monitoring of the initial plasma formation during the cu tting operation. This enhances the understanding of the oxygen effect and initiation of the cutting process.