Luca Poll

• In the context of a sustainable circular economy, the material recycling of plastic waste from additive manufacturing is becoming increasingly important. The aim of this bachelor thesis is the technical design of a cost-efficient and process-reliable recycling system that processes PLA print waste from FFF printing processes into high-quality filament. The focus is on the systematic analysis and design of the shredding unit, the extruder system, and a winding device for the extruded filament. The development process included both design and process-related considerations, supported by literature research, I calculations, and initial tests. A shredder system based on the Precious Plastic system was further developed on the basis of a materials science characterization of the print waste and economic analyses. A derived equation for the cutting force made it possible to design the mechanically stressed components to withstand the load. Initial tests showed good agreement with the theory but revealed potential for optimization with regard to material tilting. A methodology for preliminary and fine design was developed for extrusion. An equation for determining the force curve along the screw was derived from basic physical relationships. Thermal influences and process fluctuations could be specifically reduced in order to ensure constant filament quality.