Laser beam shaping in conduction-mode laser melting

What is it about?

The effects of laser beam shaping on melt-pool behaviour, solidified bead profile and microstructural gain morphology were studied comprehensively through high-fidelity numerical experiments for conduction-mode laser melting of stainless steel AISI 316L. Three-dimensional unsteady numerical simulations were performed to examine the effects of laser beam intensity profile, shape and inclination angle on the melt-pool behaviour. Critical physical phenomena in laser melting such as temporal and spatial variations of absorptivity, heat and fluid flow dynamics, solidification and melting, and free-surface oscillations were accounted for in the present computational model. Moreover, experiments were performed using different laser beam shapes and the validity of the present numerical predictions was demonstrated.

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Photo by Opt Lasers on Unsplash

Photo by Opt Lasers on Unsplash

Why is it important?

Laser beam shaping offers remarkable possibilities to control and optimise process stability and tailor material properties and structure in laser-based welding and additive manufacturing. However, little is known about the influence of laser beam shaping on the complex melt-pool behaviour, solidified melt-track bead profile and microstructural grain morphology in laser material processing. A simulation-based approach is utilised in the present work to study the effects of laser beam intensity profile and angle of incidence on the melt-pool behaviour in conduction-mode laser melting of stainless steel 316L plates. The present high-fidelity physics-based computational model accounts for crucial physical phenomena in laser material processing such as complex laser–matter interaction, solidification and melting, heat and fluid flow dynamics, and free-surface oscillations. Experiments were carried out using different laser beam shapes and the validity of the numerical predictions is demonstrated.