Ricerc@Sapienza

Selective laser melting is, at present, one of the
fastest growing additive manufacturing technologies. It allows
the manufacture of functional components characterized by
high complex geometries with engineering-grade metals.
Notwithstanding, it is employed in many industries such as
aerospace, automotive, biomedical, and defense; a great limitation
for its diffusion is the obtainable surface quality. This
work aims to improve the surface of Ti6Al4V parts produced
by this technology through barrel finishing. It is a mass
finishing operation able to condition parts by means of a soft
mechanical action provided by a granular flow. Since no part
fixing is needed and a lot of materials with complex geometries
can be processed, it is a good candidate for the conditioning
of additive-manufactured parts. An experimental plan has
been designed considering aspects such as the involved granular
motions, the charge composition, and the parts built orientation.
The barrel finishing process parameters have been
experimented by the development of the bed behavior diagrams
in order to set a parameters window adequate for the
finishing operation. The selective laser melting surface morphology
and its evolution during the barrel finishing processing
have been investigated via profilometric, macroscopic,
and microscopic analysis: this allowed the evaluation of the
conditioning action in terms of obtainable roughness and
radiusing. Results showed a marked decreasing of the average
roughness and an increasing of the edge radius. Finally, the modification in terms of dimensional accuracy and the mechanical
properties of the finished parts have been evaluated.