Role of laser power and scan speed combination on the surface quality of additive manufactured nickel-based superalloy

Abstract

In laser-based powder bed fusion (L-PBF), the volumetric energy density (VED) controlled by laser power (LP) and scan speed (SS) significantly affects the desired surface quality. Any variations in the LP and SS on the VED notably affect the surface quality due to changes in laser powder interactions. Therefore, the present study concentrated on the effect of various combinations of LP and SS, i.e. low LP (160 W) with high SS (1250 mm/s), high LP (320 W) with low SS (410 mm/s), low LP (160 W) with low SS (550 mm/s) and high LP (320 W) with high SS (1100 mm/s). The wide range of varying VEDs was chosen between 29 and 177 J/mm³. The results showed the VED range between 66 and 90 J/mm³ exhibited minimum surface roughness parameters of 0.51 < Ra < 0.52 µm, 0.63 < Rq < 0.64 µm, and 2.53 < Rz < 2.79 µm. The specific impact of LP and SS combination between 160 and 320 W with 400–1250 mm/s by maintaining a constant VED of 66 J/mm³ was also investigated. At a constant VED of 66 J/mm³, the combination of 280 W and 960 mm/s shows minimum roughness parameters of Ra = 0.527 µm, Rq = 0.645 µm, and Rz = 2.446 µm. The results showed that the combination of low LP with low SS, high LP with high SS, low LP with high SS, and high LP with low SS, increases surface roughness.