Additive Manufacturing of Polyamide-6 Preforms for Scalable Thermal Drawing of Structured Fibers

Thermal drawing is a prominent, scalable method for transforming preforms with complex macroscopic morphologies into multifunctional microscopic fibers. With the intent to develop fibers with complex cross-sections for potential integration in soft robotics, smart textile and fabric applications, we explore the potential of polyamide-6 (PA6) as a base material for thermal drawing. By implementing Fused Deposition Modeling (FDM), we additively manufactured PA6 preforms with solid circular and three-channel cross-sectional architectures. These preforms were then utilized in a series of thermal drawing experiments to identify the best-performing printing layer thickness and channel aspect ratio (AR) that consistently yielded scalable, microscopic fiber diameters over extended durations. Our results demonstrate that a printing layer thickness of 0.3 mm yielded the most consistent drawn fiber diameters for extended durations among the tested values. Additionally, AR experiments indicate that the intermediate ARs of 0.4 and 0.5 between the inner channel diameter and the outer diameter produce the most promising results within the investigated range, based on dimensional trends and qualitative observations of internal channel integrity.