Evaluation of 3D Printing process of Reed-PLA Bio composite

Abstract

This thesis presents a case study on reed-reinforced PLA bio composites produced through FGF printing and injection moulding, emphasizing process optimization throughout different production stages. This study adopts a holistic perspective by analysing the complete processing chain, including material preparation (milling, sieving, drying), twin-screw extrusion with enhanced thermal parameters, FGF printing calibration, and injection moulding (IM). The objective is to comprehend the influence of process variables on the characteristics of composites. On 22.10.2024, reed stems were collected, ground into particles of 250 μm and 500 μm, and mixed with 20 wt% of Ingeo Biopolymer 3251D. The tests on twin-screw extrusion looked at temperatures from 195 to 210°C and screw speeds from 50 to 70 rpm. The best conditions were found to be 200°C and 70 rpm, as shown by the stability of the torque. The FGF printing was calibrated in a systematic way using a Stratus3D pellet extruder, while IM used a HAAKE Minijet Pro system. Mechanical characterization was performed using Charpy impact testing and comparative tensile testing on selected specimens. Impact testing showed that adjusting the size of the particles made a big difference in performance. For example, specimens with a size of 250 μm did 43 % better than those with a size of 500 μm. At the same particle sizes, IM always produced more impact energy than FGF. This is because the fibres were randomly oriented instead of being aligned in a specific direction, as is common in extrusion-based printing. A comparative analysis with literature data for flax-PLA, hemp PLA, and jute-PLA indicates that untreated reed composites exhibit modest mechanical properties, showcasing reinforcement potential and emphasizing the advantages of chemical treatment. This case study approach clearly shows the ways to improve processing and the problems with mechanical characterization. It shows that reed-PLA is a promising sustainable material for uses that focus on improving stiffness and being good for the environment.