For the particular parameter space where laser power is held constant at 500 W and only
the scan speed is allowed to vary (420-840 mm/s), the average meltback was revealed to vary
between 0.33 and 0.48 mm and the total amount of columnar growth was in the range of 0.30
and 0.55 mm. Generally, an inverse relationship between the net columnar growth and meltback
was found (Figures 6 and 7).