Closed loop supply chain network for local and distributed plastic recycling for 3D printing: a MILP-based optimization approach

Abstract

Recent research and initiatives increasingly propose a new approach, based on distributed plastic recycling for open-source (OS) 3D printing technologies, as a way to deal with the issue of plastic waste and to support the development of the Circular Economy (CE). Distributed recycling can be thought of as a sort of "smart grid", composed of small and coordinated recycling units. However, the operational complexity of this distributed approach limits its application. Furthermore, the environmental and economic advantages have yet to be demonstrated. This article therefore explores the economic and environmental feasibility of this distributed plastic recycling approach from a logistics perspective, as a step towards its validation. To achieve this, an optimization Mixed Integer Linear Programming (MILP) model was used as an evaluation tool, representing a local Closed Loop Supply Chain (CLSC) network. The proposed model is illustrated using a case study of a university seeking to implement a distributed recycling demonstrator in order to recover 3D printing wastes from secondary schools in the northeast of France. Following this step, a sensitivity analysis was carried out considering the market variations (price of virgin plastic filament) and the amount of available plastic waste derived from the schools. The results obtained show positive economic and environmental benefits of carrying out this new method of plastic recycling. This work serves as a basis for continuing to explore the feasibility and replication of the distributed plastic recycling network in other contexts.

Partially RepRapable automated open source bag valve mask-based ventilator

“…There has already been a concerted effort to apply open source hardware and 3-D printing during the COVID-19 pandemic [23] , [24] , [25] , [26] , [27] , [28] , [29] . In addition, challenges with supply chains during any type of pandemic can be partially offset by open source recyclebots [30] , [31] , [32] , [33] , [34] and direct recycling extrusion [35] to close the loop on material supplies with local waste converted into additive manufacturing feedstock [36] , [37] , [38] , [39] , [40] , [41] . The distributed manufacturing of scientific equipment has been shown to provide custom, high-quality scientific tools for substantially lower costs than conventional proprietary products [42] , [43] , [44] , [45] , [46] .…”

Towards Distributed Recycling with Additive Manufacturing of PET Flake Feedstocks

“…In addition, as with PLA [ 29 ], ABS [ 83 ], and HDPE [ 84 ], the impact of the number of recycle loops should be investigated and compared to a filament-extruding approach for multiple cycles. This is important to have a closed-loop supply chain in the circular economy [ 12 , 85 ]. It is likely that the direct rPET FPF 3D printing demonstrated in this study would provide an advantage, as the number of melt/solidification loops would be reduced by ½.…”

Connecting the strategic intent of innovation labs and projects: the case of the Green Fablab

“…Moreover, the study of sustainable solutions developed at the LF2L ® can be part of the consolidation and reinforcement of the links with the local ecosystem in which this space is located, taking into account the strategic direction at city level in terms of ecological transition [26]. The previous studies within this project focused on the technical validation of the printing [27] and plastic recycling [28] and logistical consideration [29], [30] processes under scientific laboratory conditions. However, from a research perspective, the interest is to study how this process could be democratized based on the user/community-innovation paradigms [31], [32], enablign the notion of distributed recycling.…”