Fiber Formation of Printed Carbon Fiber/Poly (Ether Ether Ketone) with Different Nozzle Shapes

The additive manufacturing industry shows annual growth of more than 10 %. Therefore, the requirements for produced components are increasing, especially for individual medical technology applications printed from poly(ether ether ketone) (PEEK). This paper focuses on an investigation of an uninterrupted nozzle system for printing the high-performance thermoplastic PEEK with short fiber reinforcements. A custom-made nozzle design with variable outlet angle is presented and the achievable fiber length distribution and fiber orientation in the printed material are investigated. The applied nozzle angles are 60 °, 90 ° and 120 °. The geometric shape of the tip of the custom-made nozzles is comparable to that of a reference nozzle. With regard to the height profile, the inner surface is up to three times smoother. With a decreasing nozzle angle, a lower degree of fiber damage caused by deposition can be demonstrated. Thus, the process-induced shortening of the fibers decreases. The enhanced flow profile for small angles outweighs the simultaneous disadvantageous due to friction loss, shear stress and pressure drop. A clear result for the fiber orientation cannot be deduced.