Abstract
Recently, Fused Filament Fabrication (FFF), one of the most encouraging additive manufacturing (AM) techniques, has fascinated great attention. Although FFF is growing into a manufacturing device with considerable technological and material innovations, there still is a challenge to convert FFF-printed prototypes into functional objects for industrial applications. Polymer components manufactured by FFF process possess, in fact, low and anisotropic mechanical properties, compared to the same parts, obtained by using traditional building methods. The poor mechanical properties of the FFF-printed objects could be attributed to the weak interlayer bond interface that develops during the layer deposition process and to the commercial thermoplastic materials used. In order to increase the final properties of the 3D printed models, several polymer-based composites and nanocomposites have been proposed for FFF process. However, even if the mechanical properties greatly increase, these materials are not all biodegradable. Consequently, their waste disposal represents an important issue that needs an urgent solution. Several scientific researchers have therefore moved towards the development of natural or recyclable materials for FFF techniques. This review details current progress on innovative green materials for FFF, referring to all kinds of possible industrial applications, and in particular to the field of Cultural Heritage.
Highlights
Additive manufacturing (AM), known as three-dimensional (3D) printing, is a class of promising machineries that produce objects starting from computer-aided design (CAD) models, by adding materials in a layer-by-layer style [1,2,3].The layer-by-layer method allows the creation of complex geometries, such as topologically optimized, integrated and functional parts with minimum material wastage and reasonable speed [4,5]
Similar reinforced polymeric products exist on the market, for example the KLONER3D® company (IT) sells a filament for Fused Filament Fabrication (FFF) in gypsum and harmless co-polyesters called LAYBRICK, which has the appearance of a stone; the Emerging Objects company (USA) prints 3D objects in sand, stone and cement, or the FormFutura company (NE) has commercialized the filament based on polylactic acid (PLA) and stone (50%), called STONEFIL, which simulates materials such as stone, clay, terracotta, granite, as well as many other companies
The results reported by the authors indicate sufficient thermal and mechanical properties of the eco-friendly biofilament produced: the adhesion between the printed layers is adequate, as well as the resolution of the final object, so it could be used for biomedical applications or the production of everyday objects, design objects, toys, etc. [121]
Summary
Additive manufacturing (AM), known as three-dimensional (3D) printing, is a class of promising machineries that produce objects starting from computer-aided design (CAD) models, by adding materials in a layer-by-layer style [1,2,3]. AM techniques are largely classifi (from ISO/ASTM standard 52900:2015) [42]: vat polymerization (SLA); material je (Objet); binder jetting (3DP); material extrusion (ME/FDM); sheet lamination (LOM); der bed fusion (SLM/SLS); and directed energy deposition (LENS) Enough research activity has still not been performed on the relationship between process parameters and final properties of the new materials for FFF machines It would be important, for example, to increase the range of melting temperature of the materials used in FFF, to limit the negative influence of the humidity towards the standard FFF filaments and to develop different combinations of natural fibers and polymers, which are environmental friendly [43]
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