Feedstock Development for Material Extrusion-Based Printing of Ti6Al4V Parts

In this work, a holistic approach for the fabrication of dense Ti6Al4V parts via material
extrusion methods (MEX), such as fused filament fabrication (FFF) or fused feedstock deposition
(FFD), will be presented. With respect to the requirements of the printing process, a comprehensive
investigation of the feedstock development will be described. This covers mainly the amount ratio
variation of the main binder components LDPE (low-density polyethylene), HDPE (high-density
polyethylene), and wax, characterized by shear and oscillation rheology. Solid content of 60 vol%
allowed the 3D printing of even more complex small parts in a reproducible manner. In some cases,
the pellet-based FFD seems to be superior to the established FFF. After sintering, a density of 96.6%
of theory could be achieved, an additional hot isostatic pressing delivered density values better than
99% of theory. The requirements (mechanical properties, carbon, and oxygen content) for the usage
of medical implants (following ASTM F2885-17) were partially fulfilled or shortly missed.