Analytical modeling and experimental study of laser powder-fed additive manufacturing on curved substrates

Abstract

To explore the forming mechanism and the evolution laws of cladding geometry with process parameters on curved substrates for laser powder-fed additive manufacturing (LPF-AM) processes, based on the laser beam distribution and the cladding forming theory of horizontal and tilted substrates, analytical models for cladding geometric characteristics in the vertical and tilted postures of nozzles were established. LPF-AM experimental research on a curved substrate of AISI 304 steel was carried out, and the theoretical results were discussed and compared with the experimental data from the perspective of the curvature radius of the substrate, powder feed rate, scanning speed, and tilt angle of the nozzle. The results showed that the tilt angle of the nozzle was the most critical factor for the laser irradiation area and cladding width; moreover, the cladding width increased gradually as the tilt angle of the nozzle increased. The curvature radius of the substrate, powder feed rate, and scanning speed had a significant influence on the cladding height. Due to the effects of gravity, surface tension, and viscous shear force, the peak shift was proportional to the powder density and the tilt angle of the nozzle. The predicted values of the analytical models fit well with the experimental results. The prediction accuracies of the cladding width, cladding height, and peak shift theoretical models were 98.97%, 91.30%, and 76.85%, respectively. This study provides deeper insight into the ensuing cladding geometrical characteristics using LPF-AM on curved substrates.