Dross formation in the laser beam cutting (LBC) process is modeled in the present study using two main categories of parameters: (1) energy-based (e.g., laser power, scanning velocity, and focal position) and (2) gas-based (e.g., assisting gas pressure, the diameter of the nozzle, and workpiece distance). A set of comprehensive analytical and empirical models is developed to predict dross diameter during the LBC process based on these groups of parameters. First, a novel closed-form analytical model of the dross diameter based on the energy balance approach is presented. The model considers heat loss during the cutting process in terms of conduction, radiation, and evaporation latent heat energy that has not been addressed in the literature. Furthermore, regression and physical parameter modeling methods are used to develop two empirical models. The regression model includes all effective gas-based and energy-based processing parameters. In the physical model, two unique physical parameters are introduced that provide physical insight into the process. The amount of energy radiated per unit area and the amount of gas deposited per unit area is represented by energy density and gas density parameters, respectively. All models are validated by laser fiber cutting experiments on austenitic stainless steel. The accuracy of the analytical model is compared with a previous study, which indicates a reduced error as a result of considering all main heat loss terms. The results reveal that the dross diameter is dominated by gas-based rather than energy-based processing parameters.

Keywords