Non‐Planar Slicing and Inverse‐Projection Path Planning for Three‐Axis Coordinated Additive Manufacturing of Continuous Fiber Composites

ABSTRACT Non‐planar additive manufacturing (NPAM) of continuous fiber‐reinforced thermoplastic composites (CFRTP) using three‐axis coordination enables multi‐axis‐like motion through a dynamic Z ‐axis linkage algorithm. This approach improves the interlayer bonding and surface quality while expanding the design freedom for fiber path planning. However, the fixed nozzle orientation in three‐axis systems cannot adapt to surface normals in real time. When combined with the continuity and stability constraints imposed by continuous fiber deposition, this limitation results in conflicts between nozzle–surface interference and achieving high‐performance fabrication. To address these challenges, this study proposes a surface‐layering algorithm based on parameter‐space interpolation and a non‐planar path planning strategy that integrates plane‐path inverse projection and NURBS curve fitting. Smooth, conformal non‐planar paths are generated via geometric inverse projection and curvature‐adaptive interpolation, enabling continuous fiber deposition on complex surfaces. In addition, the relationship between nozzle geometry and manufacturable inclination angles was established to mitigate interference risks during three‐axis NPAM. The experimental results show that compared to planar additive manufacturing, the proposed method reduces the surface deviation by 76.27% and increases the interlayer shear strength by 677.5%. The successful fabrication of UAV wings, parabolic antenna reflector sandwich lattices, and non‐planar honeycomb structures further demonstrates the method's engineering applicability.