QUESTION 8

For the following text, indicate which would be the most appropriate aim for the research.

Material extrusion can be used to build a 3D part via extruding a thermoplastic-based filament through a hot printhead and subsequently depositing the melt in layer-by-layer. Nevertheless, the material is subjected to a three-step melt process including 1) mixing of different compounds, 2) extruding filament feedstock and 3) material extrusion. This extended processing results in a long residency time and excessive thermal decomposition of PVOH. To address this issue, a pellet-fed material extrusion system has been developed and used combining Additive manufacturing (AM) with a conventional single-screw extrusion. Pellet materials can be processed directly using this technology. Therefore, the residual time of polymer melt is significantly reduced as pre-processes to compound and extrude filament are not required. It is an ideal technology to process heat-sensitive polymers or materials that are difficult to extrude into filament with a consistent diameter. Additionally, this technology allows co-processing of multiple materials at different and variable rates fed into the extruder to fabricate a compositionally heterogeneous structure. Commercially available pellet-fed material extrusion systems include 3DDiscovery (regenHU, Switzerland) focused on biomaterials, Gigabot X (re:3D Inc., US), ATLAS (Titan Robotics, US) and BAAM (Cincinnati, US). However, these have emerged onto the market within the time-frame of this research. The vast majority of material extrusion system are still using filament feedstock. This study proposes an AM technology that is more appropriate for processing heat-sensitive material, in particular PVOH.

	A.	The aim of this project is to demonstrating 3D printing capability of PVOH structures
	B.	The aim of this research is to build a 3D part via extruding a thermoplastic-based filament via conventional AM
	C.	The aim of this research is to develop pellet-fed material extrusion system