Modulation of melt pool behaviour using novel laser beam oscillation methods

Laser-based spatial manipulation for welding, surface modification, and additive manufacturing presents challenges centred around controlling the thermal field's impact on material response. Traditional wobbling methods often struggle with weld pool stability and fluence profile control. This paper presents a novel wobbling approach aimed at precisely managing the thermal field during laser processing. The proposed approach leverages controllable parametric equations—Lissajous equations—coupled with speed modulation to eliminate turning points. This strategy stabilizes the weld pool effectively but also enables the creation of diverse fluence profiles through laser beam oscillations. The study showcases the consequences of this method on the energy delivered by the laser on the material. Its successful implementation with Ti-6Al-4V have demonstrated changed in the weld geometry and microstructural integrity. The approach yields consistent α' microstructures within prior-β grain, free from welding defects. Further development of galvanometric systems could allow the implementation of the described method to navigate between control methods and scan patterns to permit microstructural manipulation. On a broader range, the use of the scan strategies explored here presents significant advantage which allows new solutions to traditional approaches in energy beam processing for any kind of metallic alloys.