A multi‐layer approach for additive manufacturing of continuous fiber composites

Abstract Additive manufacturing (AM) of continuous fiber reinforced polymer composites (cFRPCs) requires innovative tool‐pathing strategies that account for the anisotropic properties of the continuous fibers and ensure their continuous deposition as reinforcement along the designed structure, reducing fibers bending and cutting. Existing 3D printing slicing software, designed for isotropic materials like neat polymers, has been adapted for 3D printing of continuous fiber composites, resulting in a layer‐by‐layer approach that necessitates filament cutting after each layer deposition. This method introduces discontinuities, weakening the material and underutilizing continuous fibers strength. In this research, we propose a novel tool‐pathing strategy designed to address these challenges through (1) Ensuring fiber continuity across layers by allowing overlapping filaments and (2) Strategically positioning fiber cut points based on stress distribution, modeled using finite element analysis. A Multi‐Layer Continuous Fiber Path (ML‐CFP) approach was introduced and validated on a simple bracket structure featuring two load‐application inserts. 3D printed brackets using different tool paths were tested to failure under tension and compression after compression molding to improve interlayer adhesion. Mechanical investigations confirmed that the ML‐CFP approach enhances fiber utilization, improving tensile strength and work to fracture by up to 46% and 100% through promoting failure in fibers rather than at cut points. Highlights Introduced the multi‐layer continuous fiber path method (ML‐CFP) in AM of cFRPCs. Introduced the strategic cut point placement (SCPP) based on stress distribution. Maintaining fiber continuity and reduce fiber bending by allowing filament overlap. Mechanical testing to compare the ML‐CFP with conventional slicing methods. Enhanced tensile strength by up to 46% and work to fracture by 100%.