Geometry-Driven Control of PCL Fiber Deposition in a Hybrid Electrospinning–3D Printing Platform

The reproducibility of electrospun fibrous microarchitecture remains limited by the interaction between jet instability and deposition history. This study evaluated four programmed needle trajectories—Spiral, Static, Waves, and Zig-Zag—using a hybrid electrospinning–3D-printing motion platform. Four independent deposition runs were produced per trajectory (n = 4), yielding 16 SEM datasets and 16 tensile specimens. SEM images were calibrated automatically from the 50 µm scale bar and analyzed using a common physical ROI, skeleton-based fiber-diameter estimation, pore-opening analysis, spatial coverage, segment orientation, and 2D FFT descriptors. The four motion programs generated distinct and reproducible macroscopic deposition paths, while the replicated whole-ROI scalar descriptors showed substantial overlap: mean fiber diameter, pore opening, coverage, porosity, FFT alignment, and angular spread did not differ significantly among trajectories (one-way ANOVA p = 0.726–0.985 for the principal descriptors; Kruskal–Wallis p = 0.608–0.931). PCA likewise showed substantial overlap in the reduced global-descriptor space. Maximum tensile stress was 0.185 ± 0.052, 0.227 ± 0.079, 0.214 ± 0.147, and 0.189 ± 0.051 MPa for Spiral, Waves, Static, and Zig-Zag, respectively, without a significant inter-trajectory difference (p = 0.900). These results support a two-scale interpretation: programmed XYZ geometry provides deterministic control of the macroscopic deposition path and changes the spatial history of fiber landing and overlap, whereas fiber formation and whole-ROI averaged morphology remain strongly governed by electrohydrodynamic/material conditions and deposition-to-deposition variability. These findings demonstrate the feasibility of integrating electrospinning with programmable XYZ needle motion within a custom-designed platform. Although the programmed trajectories define distinct needle-motion geometries, no statistically significant differences were detected in the principal global morphological or mechanical descriptors under the investigated conditions.