Polymer Additive Manufacturing by Fused Filament Fabrication

According to the NF EN ISO/ASTM 52900 standard, additive manufacturing (AM) encompasses technologies enabling parts to be manufactured using successive layers of material based on a digital model. First used in the late 1980s to produce prototypes, FA is now used for most parts in everyday use or in high-tech applications. It can be applied to metals, ceramics, polymers, concrete and, more recently, glass. Its field of application is growing all the time, enabling us to produce parts for cutting-edge sectors such as aeronautics, the automotive industry and healthcare.

Of all AF techniques, 3D printing using plastic extrusion accounts for a large share of the market. Known as Fused Deposition Modelling (FDM) or Fused Filament Fabrication (FFF), it is fairly easy to implement and requires moderate energy and material (thermoplastic polymer) and acquisition costs. Nevertheless, properties (mechanical, thermal) remain below those of products shaped by more conventional methods. In order to improve these properties and extend the range of applications even further, the operation of DFF printers needs to be studied in greater depth. The aim of this article is therefore to detail the key stages of the process, drawing on the first principles of physics and process engineering.

Having outlined the process in section 1 , the way in which the polymer melts in the extruder is described in section 2 . Filament deposition will then be studied in section 3, where its morphology, cooling and crystallization will be discussed. At the end of these two sections, perspectives on the FDM process will be proposed.