Plastic waste poses a significant environmental challenge globally, with roughly 300 million tons generated annually and only 5% of that amount recycled. We investigated the manufacturing feasibility of repurposing recycled plastic into a small functional consumer product through injection molding, using high-density polyethylene (HDPE) and a simplified manual injection molding system suited for small-scale manufacturing.
We compared virgin and recycled HDPE using tensile-strength and durability tests. Recycled material was sourced from post-consumer containers and processed under controlled conditions to evaluate mechanical performance. We used COMSOL Multiphysics to model polymer flow behavior and support mold design, and developed prototype molds through CAD. Product selection was informed by a student survey, which identified a keychain-sized bottle opener as the optimal design based on desirability, usability, and compatibility with our system’s constraints. We also conducted a preliminary techno-economic analysis to estimate production and material costs and assess profitability within a small-scale manufacturing model.
Our results indicate that recycled HDPE can be successfully processed into reusable products while maintaining acceptable mechanical integrity, and that small-scale production of recycled plastic goods may be economically viable. Our simplified injection molding system demonstrates a scalable framework for sustainable product development and local recycling initiatives.