Composite material created by additive manufacturing techniques FFF and Robocasting for the manufacture of medical parts

Abstract

The purpose of this study is to create a new technique of additive manufacturing that allows creating pieces of composite material for the medical industry. This material gives the pieces' characteristics such as: lightness and resistance. In addition, with the use of this material the geometry of the pieces to be built is not limited as in the systems of traditional manufacture of composite material. For this reason, we will work with thermoplastic materials and epoxy adhesives on an additive manufacturing machine based on the FFF technique. The composite material has been obtained by a new manufacturing system. An adhesive extruder head has been designed which has been manufactured using the FFF technique. This new extruder is implemented in an AM RepRap machine next to the thermoplastic filament extruder. The joint printing of both materials, in alternating layers, generates a composite material that allows to increase the structural properties of the piece in the XY plane. The new additive manufacturing system allows to obtain mechanical improvements both in the modulus of elasticity and in the tensile strength. Increase the modulus of elasticity of a value between 50-80% depending on the thermoplastic filament used. In the same way the tensile strength has increased between 50-60%. The improvement in the strength / weight ratio makes this new additive manufacturing system allows to create medical pieces in which the lightness and resistance are its main characteristic such as orthopedic prostheses. The study shows that the use of FFF together with Robocasting, as a manufacturing process for end-use parts, generates an additional advantage that had not been considered until now. The combination of a thermoplastic and an epoxy resin opens a new path in the additive manufacturing since it allows creating pieces with new qualities without being conditioned by the design.