Five-axis material extrusion of high-performance structural parts with continuous carbon fiber-reinforced LM-PAEK

Additive manufacturing (AM) offers numerous advantages over standard manufacturing methods, such as design freedom and enabling limited production run components. Using continuous fiber-reinforced polymer composites, polymer AM can now produce end-use components with mechanical properties rivaling metals. In this paper, five-axis continuous fiber material extrusion (ME) is utilized to manufacture specimens from high-performance semi-crystalline low-melt polyaryletherketone™ (LM-PAEK™) composite. ASTM standardized testing showed record matrix-dominated and flexural properties for as-printed parts, with low porosity and high crystallinity. Annealing did not change mechanical properties or crystallinity. Additionally, steering radii specimens and a complex geometric bracket were manufactured using the full out-of-plane 3D printing capability of the five-axis equipment; subsequent X-ray computed tomography showed multiple manufacturing defects and voids when printing high-curvature rasters. Results thus pave the way for using LM-PAEK™ to replace other high-performance polymers in continuous fiber AM, although designers should take note of fiber steering in critical load-bearing structures.