title: Engineering Thermoplastics for Additive Manufacturing: A Critical Perspective with Experimental Evidence to Support Functional Applications.
abstract: BACKGROUND
  Among additive manufacturing techniques, the filament-based technique involves what is referred to as fused deposition modeling (FDM). FDM materials are currently limited to a selected number of polymers. The present study focused on investigating the potential of using high-end engineering polymers in FDM. In addition, a critical review of the materials available on the market compared with those studied here was completed.
  
  
  METHODS
  Different engineering thermoplastics, ranging from industrial grade polycarbonates to novel polyetheretherketones (PEEKs), were processed by FDM. Prior to this, for innovative filaments based on PEEK, extrusion processing was carried out. Mechanical properties (i.e., tensile and flexural) were investigated for each extruded material. An industrial-type FDM machine (Stratasys Fortus® 400 mc) was used to fully characterize the effect of printing parameters on the mechanical properties of polycarbonate. The obtained properties were compared with samples obtained by injection molding. Finally, FDM samples made of PEEK were also characterized and compared with those obtained by injection molding.
  
  
  RESULTS
  The effect of raster to raster air gap and raster angle on tensile and flexural properties of printed PC was evidenced; the potential of PEEK filaments, as novel FDM material, was highlighted in comparison to state of the art materials.
  
  
  CONCLUSIONS
  Comparison with injection molded parts allowed to better understand FDM potential for functional applications. The study discussed pros and cons of the different materials. Finally, the development of novel PEEK filaments achieved important results offering a novel solution to the market when high mechanical and thermal properties are required.
authors.affiliation:  Department for Civil Engineering and Architecture, University of Catania, Catania - Italy.| UdR National Interuniversity Consortium of Materials Science and Technology, Florence - Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Cicala
authors.affiliation:  Department for Civil Engineering and Architecture, University of Catania, Catania - Italy.| UdR National Interuniversity Consortium of Materials Science and Technology, Florence - Italy.
authors.forename: Alberta
authors.initials: A
authors.lastname: Latteri
authors.affiliation:  UdR National Interuniversity Consortium of Materials Science and Technology, Florence - Italy.| Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan - Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Del Curto
authors.affiliation:  Roboze, Bari - Italy.
authors.forename: Alessio
authors.initials: A
authors.lastname: Lo Russo
authors.affiliation:  National Research Council, Institute for Polymers Composites and Biomaterials, Catania - Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Recca
authors.affiliation:  UdR National Interuniversity Consortium of Materials Science and Technology, Florence - Italy.| Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan - Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Farè
keywords: Additive manufacturing; Cellulose reinforcement; Composite; Engineering thermoplastics