Coaxial laser melting is a method of manufacturing metal parts related to additive manufacturing processes significantly reducing the manufacturing time and cost of complex geometry parts in single and small batch production, as well as reducing material losses during machining. The typical objects of this technology are parts containing thin-walled structures. Determining coaxial laser melting regimes of such structures when grown under conditions of varying heat sink is a daunting task, and numerous papers devoted to the analysis of the influence of process parameters on the geometry of the forming clads are contradictory and do not always take into account the limited heat capacity of the thin walls. Based on the results of the experiment using the mathematical planning method, regression models for calculating the dimensions of the upper forming clads for thin-walled structures made of corrosion-resistant steel 316L were obtained. The relationship between the main parameters of the coaxial laser melting regime and the geometric characteristics of single clads has been established. A complete correlation of the experimental and calculated data was found, as well as a high accuracy in predicting the results. The analysis of regression characteristics allowed finding the optimal regimes of coaxial laser melting i.e. the maximum cross-sectional area with the minimum substrate penetration.

Coaxial laser melting (CLM) is a method of additive manufacturing. In CLM, parts are produced by melting powder particles that reach the application area, layer by layer, using a laser beam. When growing thin-walled structures, it becomes necessary to control the parameters of coaxial laser melting to maintain the thermal environment in the surfacing zone. Experimental studies of the relationship between the thermal distribution and the output structure are time-consuming and have low reliability of the result due to the complexity of registering temperature fields under conditions of changes in the growing process. For this reason, modeling processes of additive technology has been actively developing recently. A model for calculating the heat cycle, maximum temperature, and volume of the molten pool during coaxial laser melting of a thin wall made of 316L stainless steel powder is proposed. Based on the calculation, the relationship between the dimensions of the molten pool and heat distribution with the number of deposited metal layers was established.