U-turn precision of robot-based 3D printing for continuous fiber reinforced thermoplastic composite

Purpose This study aims to enhance U-turn precision in robotic three-dimensional (3D) printing of continuous fiber reinforced thermoplastics for near-net-shape manufacturing by analyzing fiber bundle shifting and width variation to optimize process parameters. Design/methodology/approach A six-axis robotic fused filament fabrication system was developed with a preprinting tool center point calibration method that reduced X-direction deviations by 80% (280→32µm). L9(34)orthogonal experiments evaluated printing speed (120–240 mm/min), turning radius (0.5–1.5 mm), feeding ratio (40%–60%) and retraction control. Findings Turning radius significantly impacted accuracy (p < 0.1). Optimal parameters (1.5 mm radius, 120 mm/min speed, 60% feeding, enabled retraction) achieved 244 µm shifting and 0.19% width error. Specimens showed 167.9 µm (flat) and 89.6 µm (curved) average accuracy, with edge deviations reaching ±1.78 mm. Originality/value This study provides practical solutions for high-precision continuous fiber reinforced thermoplastic composites manufacturing and establishes a framework for optimizing robotic 3D printing in aerospace and automotive applications, while guiding future thermal and extrusion research.