Synergistic optimization of geometry, mechanics, and kinematics for multi-axis support-free additive manufacturing of continuous fiber reinforced composites

Multi-axis additive manufacturing (MA-AM) enables the support-free fabrication of continuous fiber reinforced composites (CFRC), but practical implementation requires coordinated planning of slicing layer geometry, fiber toolpath topology, and manipulator kinematics. This study develops an integrated process-planning framework that links these stages through constraint forwarding. A vector field optimization (VFO) model accounts for overhang, directional variation, and stress alignment when generating curved slicing layers. Fragmented stress-aligned contours are then connected through Eulerian graph reconstruction to form a continuous fiber toolpath without retraction between disconnected deposition segments. At the robot-planning stage, a layer-wise kinematic optimizer exploits rotation about the printing nozzle axis to avoid low-manipulability configurations and reduce joint variation. Collision-witness verification further identifies layers that require local geometric regeneration. In repeated coupon tests ( n = 3 per group), the proposed fiber toolpath produced a mean ultimate load of 610.00 ± 6.24 N, representing increases of 28.4% and 8.4% over the 45° and 30° raster baselines, respectively. The layer-wise kinematic strategy reduced Total Joint Variation (TJV) by 17.22% relative to point-wise inverse kinematics (IK). In the closed-overhang case, two accepted feedback updates increased the minimum signed clearance from −1.016 to 13.492 mm at the sampled IK waypoints under the capsule–voxel model. This sampled result does not constitute a continuous-time collision certificate. The results show that slicing geometry, fiber toolpath topology, and robotic execution can be coordinated within a unified offline planning framework.