Mechanics-Guided Optimization of Dimensional Fidelity in Continuous Basalt Fiber-Reinforced PLA

Continuous-fiber reinforcement is one of the most practical ways to turn material-extrusion 3D printing into a process suitable for structural applications. Basalt fiber is particularly interesting here because it offers stiffness comparable to glass fiber and comes from a single natural mineral source, making it a potentially more sustainable option. However, there is a key challenge. When a stiff fiber is embedded into a semi-molten thermoplastic during printing, the print head has to guide it through curves and corners. This often leads to small deviations from the intended path, especially at sharp turns. These errors can shift fiber placement, change wall thickness, and create stress concentrations, issues that are critical in anisotropic composite materials.

In this work, we propose a mechanics-based framework to improve dimensional accuracy in continuous basalt fiber-reinforced PLA (CBF-PLA). The approach introduces a printable-curvature criterion that connects fiber tension, nozzle design, and interfacial behavior to the maximum achievable curvature. It also includes a structured experimental plan to separately evaluate global warping and local geometric deviations. By treating toolpath smoothing and corner compensation as key design variables, the framework offers a clear, mechanism-driven way to achieve more reliable and accurate printed structures.