Design & Development of a Plastic Filament Extrusion Machine

The objective of this project was to produce plastic filament suitable for use with Rep Rap 3D printers from raw plastic pellets or recycled plastic waste for the UBC Rapid student team. The specifications for the filament required that it be of similar quality to commercial filaments, smooth and with minimal bubbles with a constant diameter of about 3mm.To accomplish this end, a prototype plastic extruder was designed, constructed and tested. The prototype was tested running at different speeds and temperatures to determine a good operating point. The investigation showed that extrusion of plastic filament of comparable quality to commercial filaments is possible with careful operation. The diameter is the most critical feature and is dependent on the rate at which the filament is drawn away from the die as well as a steady input to the heating pipe. With an out feed mechanism, the filament could be drawn at constant rate to form a constant diameter.