Laser direct fabrication and characterization of 3d lattice structures using continuous carbon fiber thermoset composites

Continuous carbon fiber reinforced thermoset composites are high-strength, lightweight materials with high temperature and corrosion resistance that can be widely used in aerospace and other fields. Direct manufacturing of complex lattice structures remains challenging for manual assembly or existing additive manufacturing (AM) technologies. In this study, we developed a novel strategy to directly cure and print continuous carbon fiber (CCF) thermoset composite lattice structures under high laser intensity. Taking advantage of dual-cure characteristics of the photopolymer resin being used in this study through ultraviolet (UV) and thermal curing, 3D printed complex CCF lattice truss structures are self-supporting with rapid laser curing of the resin matrix material, thus eliminating the necessity of using support structures during 3D printing. The mechanical properties of the 3D printed carbon fiber lattice structure were experimentally measured through compression tests. The maximum compressive strength and the maximum compressive modulus were found to be 2.28 MPa and 4.48 MPa, respectively. A good agreement was also found in comparison with numerical simulations. With the AM method described here, to the best of our knowledge, this is the first study presenting direct 3D printing and characterization of CCF lattice structures with thermoset composites. It is also the first investigation to successfully print thermoset composite lattice structures and analyze their mechanical properties. It was also found that high laser intensity has a significant impact on the curing of thermoplastic materials. This method of laser printing and the choice of materials could serve as a basis for future research on thermoset composites. The findings open new avenues and provide insights in design and manufacturing of complex lattice structures using continuous carbon fiber reinforced thermoset composites.