Technical pathways for distributed recycling of polymer composites for distributed manufacturing: Windshield wiper blades

Centralized waste plastic recycling is economically challenging, yet distributed recycling and additive manufacturing (DRAM) provides consumers with direct economic incentives to recycle. This study explores the technical pathways for DRAM of complex polymer composites using a case study of windshield wiper blades. These blades are a thermoplastic composite made up of a soft (flexible) and hard (less flexible) material. The distributed manufacturing methods included mechanical grinding to fused granular fabrication, heated syringe printing, 3-D printed molds coupled to injection molding and filament production in a recyclebot to fused filament fabrication. The particle size, angle of repose, thermal and rheological properties are characterized for the two sub-materials to define the conditions for the extrusion. A successful pathway for fabricating new products was found and the mechanical properties of the resultant components were quantified. Finally, the means to convert scrap windshield wiper blades into useful, high-value, bespoke biomedical products of fingertip grips for hand prosthetics was demonstrated. This study showed that the DRAM model of materials recycling can be used to improve the variety of solutions for a circular economy.