Laser Oscillation Diameter Variation Effect on Laser Wire Additive Manufacturing Deposition Morphology

A high-speed camera was employed to capture the melting process and investigate the impact of laser beam oscillation diameter on weld pool fluctuation and deposition morphology during laser wire additive manufacturing (LWAM) of 316L wire. The transient fluctuations of the weld pool caused by the laser beam were observed at different oscillation diameters. Additionally, 3D morphology measurements were conducted on the deposited layer to assess the effects of different oscillation diameters on its morphology. Further analysis examined the heat dispersion resulting from beam oscillation by plotting the energy distribution for various oscillation diameters. The key findings are as follows: Changes in oscillation diameter resulted in fluctuations within the weld pool that impacted the surface morphology of the deposit and refinement of pore condition as well as alterations in the energy distribution of the weld pool that influenced its contour geometry. Increasing the laser oscillation diameter can effectively make the keyhole shallower, weaken the bottom protrusion of the weld pool, and reduce the curvature of the top surface of the bead. Simultaneously, it can promote the stirring of the liquid solution, effectively refining the porosity area, reducing porosity within the weld pool, and improving the specimen’s density. However, larger oscillation diameters lead to more-significant hump arch formation on the deposited surface and larger roughness values.