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<abstract> <p>In recent years, recycling of plastics has opened several doors of advancements in the field of additive manufacturing (AM). The process of fused deposition modelling (FDM) has already been utilized for reprocessing waste plastics into filaments and finally printing them into useful products. Yet another concept of extrusion additive manufacturing (EAM) is gaining lots of attention. In this work, a screw assisted system based on EAM is designed and installed alongside a pre-existing FDM system. This system is referred to as the direct FDM (DFDM) system throughout this work. The DFDM system used operates with a 1.75 mm nozzle and has the ability of giving a high throughput. The focus of this work is to use this hybrid system (combination of FDM and DFDM systems) to print both virgin as well as recycled plastics. The scope of this work is to use one technology (either FDM or DFDM) at a time and to use both simultaneously for multi-material printing in future. After several trials of printing and setting up some printing parameters, the proposed system has been able to print with virgin as well as recycled PLA.</p> </abstract>

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Distributed Recycling via Additive Manufacturing (DRAM) is a closed-loop material reprocessing solution that promotes circular economy. There are several literature gaps related to material properties and recycling cycles at different stages of the DRAM process. With an approach to filling these gaps, a small contribution has been made through this work by comparing the effect of reprocessing cycles (recycling) with the effect of FDM printing parameters such as Raster angle orientation, Infill density and Extrusion Temperature. These four parameters are ranked based on their impact on the tensile properties of Polylactic Acid (PLA) dog bone specimens. The Design of Experiments via Taguchi Analysis is carried out to avoid analysis of a large number of samples. The results show that recycling has the maximum impact on the tensile properties of PLA samples and can reduce the tensile strength by up to 75% in the course of four reprocessing cycles. The specimens had Ultimate Tensile Strength (UTS) values in the range of 20–26 MPa at the first reprocessing cycle which dropped significantly to a range of 7–9 MPa after the fourth reprocessing cycle. Additionally, a novel analysis on time and the number of specimens to be 3D printed at each reprocessing stage has also been conducted to help future researchers manage their printing schedule, especially in the recycling domain.

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