Effects of selective laser melting parameters on surface quality and densification behaviours of pure nickel

The effects of laser power and scanning speed on the forming characteristic of scanning tracks, densification behaviours and surface roughness of pure nickel fabricated with selective laser melting (SLM) were studied. The results indicate that the scanning tracks showed continuous, regular and flat surface with increasing laser power and decreasing scanning speed in a specific range, which could avoid the defects (like holes and balling structures) forming in SLM processing. The optimal process window was identified as the scanning speed of 900 mm/s and the laser power of 255−275 W by comparing the surface qualities and densification behaviours. With the suitable processing parameters, the relative density could achieve 99.16%, the tensile strength was (359.49±2.74) MPa, and the roughnesses of the top and side surfaces were (12.88±2.23) and (14.98±0.69) μm, respectively.