Characterisation of fibre materials and treatments for continuous carbon fibre-reinforcement in a novel laser-sintering process

Additive manufacturing of continuous carbon fibre reinforced polymer (CCFRP) parts enables the economical production of complex parts for aerospace, engineering and other industries. With continuous fibres, the mechanical properties of the parts can be significantly increased in accordance with the load path. The matrix requirements for such applications however, can only optimally be met by laser sintering. The advantages of CCFRP and laser-sintering have been combined in a novel laser-sintering machine with automated continuous fibre integration. The paper describes the experiments to determine the range of possible fiber materials for in-tegration and the characterization of these. Examined were commingled yarns, pre-impreg-nated fibres and coated rovings and tested for integration, the resulting pore structure and the adhesion between fibre and matrix. Considering the process limitations, it was shown that the inherent stiffness of coated fibers around 2 mN/cm² was optimal for the mechanical design of the system.