Investigation of the Effects of Process Parameters on Fibre Orientation and Mechanical Properties of Single Strands Extruded via Robotic Screw Extrusion Additive Manufacturing

Abstract

This study investigates the influence of process parameters on fiber orientation and mechanical properties of single strands extruded via robotic screw extrusion additive manufacturing (AM). A fractional factorial design was employed to systematically analyze how nozzle diameter (D), volume flow rate (Q), the ratio of strand width to nozzle diameter (W/D), and the ratio of layer thickness to nozzle diameter (T/D) impact the alignment index and ultimate tensile strength of the extruded strands. Subsequently, microscopy and tensile testing were performed to examine the effects of changes in parameters on fiber orientation and mechanical strength. Results indicate that smaller nozzle diameters and higher volume flow rates significantly improve fiber alignment and mechanical properties such as tensile strength and stiffness. In contrast, larger W/D and T/D ratios tend to diminish these properties. Although predictive modeling using machine learning provided further insights into the effects of these parameters, the effectiveness of these models was limited by the small dataset and the presence of outliers. This research underscores the critical role of parameter optimization in enhancing the performance of fiber-reinforced composites produced through robotic screw extrusion, offering substantial benefits for industries requiring materials with specific mechanical characteristics.