Stress field-aware infill toolpath generation for additive manufacturing of continuous fiber reinforced polymer composites

The infill toolpath utilized in continuous fiber reinforced polymer composites via additive manufacturing (CFRPCs-AM) significantly influences the mechanical performance of printed structures. However, existing infill toolpath for CFRPCs-AM are primarily designed for 2D planar structures and do not account for 3D shell structures with complex shapes or load path dependent characteristics. To address these limitations, this paper proposes an explicit streamline tracing method to convert the stress field into adaptive infill toolpaths for CFRPCs-AM. The method leverages principal stress direction and value fields to control toolpath density and distribution while considering the minimum allowable bead width constraint. Additionally, the geodesic distance is employed to precisely represent the distance between adjacent infill toolpaths on shell structures. Experimental validation on 2D and 3D complex structures under varying conditions demonstrates the effectiveness of the proposed method, which significantly improves stiffness and strength by 200–300% compared to traditional uniform toolpaths for CFRPCs-AM.