Integrating CDIO framework into polymer engineering education: A hands-on approach to design, process, and evaluate biodegradable 3D printing filaments

Abstract

This study introduces a hands-on polymer engineering curriculum integrating the Conceive-Design-Implement-Operate (CDIO) framework to bridge material design, processing, and evaluation of biodegradable 3D printing filaments. To address the brittleness of polylactic acid (PLA), students formulated PLA/poly (butylene succinate) (PBS) blends with an epoxy-based compatibilizer (ADR) and compounded pellets via twin-screw extrusion. Specimens for mechanical test were fabricated using an industrial-grade injection molding machine, with processing parameters guided by Moldex3D melt flow simulations. Continuous filaments (1.75 ± 0.05 mm diameter) were produced via single-screw extrusion with real-time filament diameter monitoring. The performance of the material formulations was evaluated through mechanical testing, rheological measurements, and assessment of the 3D printing quality. Students achieved successful filament printing in 100 % of cases (vs. <50 % in the prior year), attributed to simulation-aided parameter optimization, historical data sharing, and structured feedback mechanisms. Systematic analyses established the interplay between material formulation, processability, and mechanical properties. Evaluations of student performance demonstrated enhanced technical skills (27/34 students scored B or higher) and sustainability-driven problem-solving abilities. This curriculum bridges theoretical knowledge with industrial applications, offering a scalable model for sustainable engineering education.