| Abstract Scope |
In this study, raster scanning is studied to investigate the effect of the scan length and the hatch spacing on the melt pool size at different locations along the laser travel direction. The multi-track specimens with different scan lengths are fabricated using 195 W laser power, three scan speeds (375 mm/s, 750 mm/s, and 1500 mm/s), and two hatch spacing levels (80 µm and 120 µm). The melt pool boundary obtained from both experiments and particle-scale simulations reveals that the effect of residual heat is most manifested at a laser turn region. Besides, the depth of the melt pool increases with increasing track numbers, while the track height decreases. In addition, the second-layer scanning simulation shows that the inherent surface morphology from the first layer leads to the noticeable variability in the actual powder layer thickness of the second layer which in turn impacts the melt pool in second-layer scanning. |