Abstract
To examine the impact of defocusing amount on the deposition accuracy in the Laser Wire Additive Manufacturing (LWAM) process, a one-factor variable experiment was designed. This experiment analyzed the plasma plume geometry, melting pool spatter, and melting pool length, along with observing bead geometry and porosity. The following conclusions are drawn: Variations in defocusing amount caused changes in energy distribution, which affected the stability of the LWAM process and led to changes in the surface accuracy of the deposited layer and the melt pool morphology. Increasing the defocusing amount enlarged the spot area, diminished laser power density, and effectively reduced spattering during LWAM. Surface roughness increased with defocusing, transforming the hump morphology from an initial smooth fish-scale pattern to a periodic undulating pattern. Larger defocusing decreases the melt pool area and keyhole depth, this reduction aids gas escape from the keyhole, thus mitigating porosity defects in LWAM.