Abstract: In this paper, the effect of building direction relative to the substrate (0°, 45°, and 90°) on the surface roughness of Ti6Al4V samples produced by selective laser melting (SLM) has been investigated. After SLM, the samples were subjected to different surface modifications, including acid etching (E) with HF, sandblasting (S) with Al2O3 and sandblasting + etching (SE). Surface roughness of the prepared samples were investigated by Alicona Infinite Focus optical microscopy and Scanning Electron Microscopy (SEM). It was found that there is an inverse relationship between surface roughness and building directions. Additionally, the results showed that the acid etching process increases the surface roughness of the samples at 45° and 90°, while the surface roughness decreases at 0°. Furthermore, the results showed that sandblasting and sandblasting followed with acid etching (SE) effectively reduced the surface roughness of the samples at all building directions. In summary, the acid-etched Ti6Al4V surfaces manufactured at 90° showed a superior surface roughness (Ra = 4.25 ± 0.21, Rz = 29.63 ± 2.34 μm) among the specimens, which is encouraged osseointegration of implants.

This work aimed to comprehensively evaluate the influence of different surface modifications on the surface roughness of Ti6Al4V alloys produced by selective laser melting (SLM), casting and wrought. The Ti6Al4V surface was treated using blasting with Al2O3 (70–100 µm) and ZrO2 (50–130 µm) particles, acid etching with 0.017 mol/dm³ hydrofluoric acids (HF) for 120 s, and a combination of blasting and acid etching (SLA). It was found that the optimization of the surface roughness of Ti6Al4V parts produced by SLM differs significantly from those produced by casting or wrought processes. Experimental results showed that Ti6Al4V alloys produced by SLM and blasting with Al2O3 followed by HF etching had a higher surface roughness (Ra = 2.043 µm, Rz = 11.742 µm), whereas cast and wrought Ti6Al4V components had surface roughness values of (Ra = 1.466, Rz = 9.428 m) and (Ra = 0.940, Rz = 7.963 m), respectively. For Ti6Al4V parts blasted with ZrO2 and then etched by HF, the wrought Ti6Al4V parts exhibited higher surface roughness (Ra = 1.631 µm, Rz = 10.953 µm) than the SLM Ti6Al4V parts (Ra = 1.336 µm, Rz = 10.353 µm) and the cast Ti6Al4V parts (Ra = 1.075 µm, Rz = 8.904 µm).