Extrusion-based additive manufacturing technologies: State of the art and future perspectives

Extrusion-based additive manufacturing (AM) has recently become widespread for the layer-by-layer fabrication of three-dimensional prototypes and components even with highly complex shapes. This technology involves extrusion through a nozzle by means of a plunger-, filament- or screw-based mechanism; where necessary, this is preceded by heating of the feedstock material to reduce its viscosity sufficiently to facilitate extrusion. Extrusion-based AM offers greater design freedom, larger building volumes and more cost-efficient production than liquid- and powder-based AM processes. Although this technology was originally developed for polymeric filament materials, it is now increasingly applied to a wide…