Sustainable large-format additive manufacturing of composite molds with 45-degree deposition strategies

Military missions in hostile environments are often costly and unpredictable, with squadrons sometimes facing isolation and resource scarcity. In such scenarios, critical components in vehicles, drones, and energy generators may require structural reinforcement or repair due to damage. This paper proposes a portable, on-site production method for molds under challenging conditions, where material supply is limited. The method utilizes large format additive manufacturing (LFAM) with recycled composite materials, sourced from end-of-life components and waste, as feedstock. The study investigates the microstructural effects of recycling through shredding techniques, using microscopic imaging. Three potential defense-sector applications are explored, specifically in the aerospace, automotive, and energy industries. Additionally, the influence of key printing parameters, particularly non-parallel plane deposition at a 45-degree angle, on the mechanical behavior of ABS reinforced with 20% glass fiber (GF) is examined. The results demonstrate the feasibility of this manufacturing approach, highlighting reductions in waste material and production times compared to traditional methods. Shorter layer times were found to reduce thermal gradients between layers, thereby improving layer adhesion. While 45-degree deposition enhanced Young's modulus, it slightly reduced interlayer adhesion quality. Furthermore, recycling-induced fiber length reduction led to material degradation, aligning with findings from previous studies. Challenges encountered during implementation included weak part adherence to the print bed and local excess material deposition. Overall, the proposed methodology offers a cost-effective alternative to traditional CNC machining for mold production, demonstrating its potential for on-demand manufacturing in resource-constrained environments.