Design of load-carrying components obtained by additive manufacturing subjected to
cyclic load is widely investigated. Factors such as surface quality, microstructural defects, printing
orientation, residual stress, heat treatment, geometry and size are the main variables involved
in the fatigue assessment of these components. A deeper understanding of the aforementioned
variables effects is necessary and it has been mainly investigated by experimental studies.
This study investigated the effects of of the 'as-built' condition on the fatigue properties of
an Ti6Al4V alloy manufactured by SLM in different orientations and annealed . The bending
fatigue results and surface quality assessment did not evidence a strong correlation with roughness
parameters. On the other hand, an analysis based on the size of the features at the fracture origin
proved to be successfull as a surface rating.
Analyses including the 'short crack effect'  allowed us to estimate Equivalent Initial Flaw
Size (EIFS) close to the real critical features [2, 3]. The EIFS allowed to fairly predict the life of
specimens tested in the different orientations.