3D Printing of Continuous Carbon Fiber-Reinforced Polymer Tee Pipe: Strategy Development and Demonstrator Fabrication

Abstract:

Conventional manufacturing techniques for continuous carbon fiber-reinforced polymers (CFRP) rely on costly, geometry-specific molds, which substantially limit design flexibility. To overcome these constraints, this paper proposes a robot-based, multi-axis Fused Filament Fabrication (FFF) approach for the production of CFRP components of complex geometries. The setup enables advanced material placement so that support structures and internal cores can be avoided, thereby reducing process preparation effort, post-processing requirements, and overall manufacturing cost. As a case study, a tee pipe geometry is investigated. A dedicated slicing strategy is developed in which the main pipe and the branching section are fabricated sequentially. This approach requires precise cutting and controlled re-adhesion of the CFRP material, a critical capability for extending conventional neat-polymer FFF processes to the additive manufacturing of CFRP. Experimental validation demonstrated the feasibility of the process, highlighting the critical role of an innovative technique called nozzle ironing for surface preparation, as well as the challenges associated with fiber cutting mechanisms. While the final component achieved structural coherence, leakage testing revealed porosity at specific interface regions, suggesting directions for future hardware refinement and process optimization.

• Periodical: Key Engineering Materials (Volume 1047)
• Pages: 277-286
• Online since: April 2026
• Authors: Mattes Rix, Zsolt Kallai*, Johann Kipping, Thorsten Schüppstuhl
• Keywords: 3D Printing, Carbon Fiber Pipes, Continuous Carbon Fiber-Reinforced Polymers, Tee Pipe

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