Hybrid additive manufacturing of highly sustainable Polylactic acid -Carbon Fiber-Polylactic acid sandwiched composite structures: Optimization and machine learning

Carbon fibre (CF) based polymeric composites are being used in automobile and aviation applications due to their lightweight, excellent mechanical and physical properties. In this study, the fused filament fabrication (FFF) technique was used to prepare composite structures of polylactic acid (PLA) sandwiched with CF layers followed by prediction of optimum setting by machine learning (ML). In the first stage, PLA-CF-PLA based composite structures (as per ASTM D638 type IV) were manufactured with deposition of fibre at various angles (0 degrees, 45 degrees and 90 degrees), nozzle temperature (200 degrees C, 205 degrees C and 210 degrees C) and bed temperature (55 degrees C, 60 degrees C and 65 degrees C). Further, the prepared composite structures were subjected to tensile testing (strength at peak and break, strain at peak and break, Young's modulus and modulus of toughness) followed by fracture analysis through a scanning electron microscope (SEM) energy-dispersive spectroscopy (EDS). The results of the study are supported by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR) analysis, and differential scanning calorimetry (DSC). In the second stage, Classification and Regression Trees (CART) of the ML approach were used to model strength at peak and strength at break. The results of the study have highlighted that combination of parameters, 0orientation of CF deposition, 205 degrees C nozzle temperature, and 55 degrees C bed temperature are the optimum settings for manufacturing PLA-CF composite structures. The ML CART model is a valuable tool for predicting the strength at peak and strength at break hybrid additive manufacturing of highly sustainable PLA-CF-PLA sandwiched composite structures.